Two Stroke Motocross » Tests

Dirt Rider – KTM 150 vs. 250F

JohnNicholas — Sat, 30 Oct 2010 19:53:28 +0000

In the November 2010 issue of Dirt Rider magazine, they did a comparison test. Putting the two-stroke KTM 150 against the KTM 250F. The results are a bit different than you might expect. It’s a worthwhile test to read. Please post your comments and opinions below.

http://www.dirtrider.com/reviews/motocross/141_1011_ktm_150_sx_vs_ktm_250_sxf_small_bore_motocross/index.html

REAL TESTS! 2010 MXA RACE TEST OF THE 2010 YAMAHA YZ250

Jody Weisel — Tue, 27 Jul 2010 22:10:43 +0000

We hate to say it, but the difference between a four-stroke and a two-stroke is night and day. A two-stroke wheelies, roosts and rockets around the track— A four-stroke feels more like driving a truck.

Q: FIRST AND FOREMOST, IS THE 2010 YAMAHA YZ250 BETTER THAN THE 2009 YZ250?
A: No. It is identical to last year’s model. Well, not identical, because there were two changes from 2009 to 2010:

(1) The right-side gas tank graphics are new.

(2) The left-side gas tank graphics are new.

2010 Yamaha YZ250. Photo by MXA

Q: HOW CAN YAMAHA GET AWAY WITH NOT MAKING ANY CHANGES TO THE 2010 YZ250?
A: They can “get away” with not changing the 2010 YZ250 because it is as close to perfect as a showroom stock motorcycle can get.

Q: COULD YAMAHA’S ENGINEERS MAKE THE 2010 YZ250 BETTER?
A: Yes, they could. Every manufacturer could make their bikes better if they had the budget. But, and this is a big but, the budget for any given model is determined by “return on investment.” Before investing a million dollars into more horsepower, sleeker ergos or whiz-bang gizmos, the bean counters have to determine whether the costs of development will be offset by an increase in sales.

Unfortunately, the current market doesn’t look good when it comes to return on investment—and the return on two-strokes is even less than on the poor-selling four-strokes. Thus, Yamaha decided to stand pat on the 2010 YZ250.

Q: WHAT CHANGES WOULD WE LIKE TO SEE YAMAHA MAKE TO THE YZ250 TWO-STROKE?
A: Here is the short list:

(1) Horsepower. The YZ250 has good power and a sweet two-stroke powerband, but it isn’t the most powerful 250 two-stroke sold. If the YZ250 had KTM’s 49 horsepower with the YZ’s powerband, it would be a missile.

(2) Weight. It’s not heavy, but it could be lighter. The AMA allows a 250 two-stroke to weigh 212 pounds (a 450 four-stroke has a 220-pound minimum limit). On the showroom floor, the YZ250 could easily be 5 pounds lighter.

(3) Cosmetics. As new models come out, the tastes of the riders change. Bikes designed in the last couple years are flatter, sharper and more modern looking. The YZ250, which hasn’t seen a major change since 2006, looks rounder. It’s
dated.

(4) Suspension. We have no complaints about the performance of the YZ250′s Kayaba SSS suspension. It is sweet. But, and you knew a but was coming, the YZ250 still uses the old-style shock linkage (that is mounted through the swingarm instead of slung under it).

(5) Accouterments. A handful of the parts on the YZ250 are old-school. For example, the YZ-F bikes have 25mm rear axles. The YZ250 still has the older model 22mm axles. We’d like it to get the new swingarm, shock linkage, triple clamps, rear hub, clutch lever and zinc-coated chain.

2010 Yamaha YZ250: If you want to own a trouble-free machine that doesn’t cost an arm and a leg to maintain—this is it. Photo by MXA

Q: WHAT ARE THE BIG PLUSES OF THE 2010 YAMAHA YZ250?
A: Here is where a YZ250 two-stroke shines.

(1) Price. The retail price of a 2010 Yamaha YZ250 is $6999. The 2010 YZ450F costs $7990. The YZ250 retails for a grand less than its 450 brethren.

(2) Maintenance cost. To rebuild a YZ250, all it requires are a piston, rings and gaskets. The top-end kit (piston, rings, circlips and wrist pin) retails for less than $175. The same parts for a YZ450F (piston, rings, circlips and wrist pin) run over $250. And it should be noted that rarely will you be able to get away with just changing a four-stroke piston without checking the valves, valve seals, valve springs, keepers and cam chain.

(3) Titanium shock spring. Yamaha removed the Ti shock spring from its four-stroke line, but the YZ250 has a titanium shock spring. It would cost $600 to buy this spring from your dealer.

(4) Weight. No contest. A YZ250 comes in 12 pounds lighter than a YZ450F.

(5) Line choice. The snappy power of the two-stroke has more of a tendency to lift the front wheel, break traction and spin the rear tire. As a result, the bike turns from the rear. It likes to powerslide and explode out of turns. In soft dirt, whoops and loam, the two-stroke gets on top of the dirt much quicker than a four-stroke. It’s more willing to make quick direction changes and switch lines on a whim. YZ250 two-stroke riders are rewarded for seeking out good dirt and taking the bull by the horns. The power delivery of the two-stroke makes it feel even lighter than it is.

(6) Fun factor. We hate to say it, but the difference between racing a four-stroke and a two-stroke is night and day. A two-stroke wheelies, spins, roosts and rockets around the track—even if you’re going slow. A four-stroke drones around the track and feels more like driving a car than a classic dirt bike. Two-strokes are fun to ride at any speed.

Q: HOW DOES THE YZ250 TWO-STROKE COMPARE TO THE YZ250F FOUR-STROKE?
A: No contest. In most amateur racing organizations, a 250cc two-stroke is legal in the 250 four-stroke class. When compared to a 250 four-stroke, the YZ250 makes nine horsepower more than a 250cc four-stroke—it is does it with one-third the moving parts. swing radically in favor of the 250cc two-stroke.
(1) Power. The YZ250 two-stroke makes 45.5 horse-power, while the YZ250F only produces 36.3 horsepower. That is a nine horsepower advantage for the 250 two-stroke.

(2) Lap times. In back-to-back testing, the MXA wrecking crew discovered that, on average, lap times were identical between a YZ250 two-stroke and YZ250F four-stroke. Logic says since lap times are virtually identical, the man who gets to the first turn first should win. With a nine horsepower headstart, if a 250cc two-stroke doesn’t beat a 250cc four-stroke to the first turn, the rider needs to work on his technique.

Q: IS THE 2010 YZ250 FASTER THAN A 2010 YZ450F?
A: No. Of course not. Simple logic will clue you in to the fact that a 450cc engine makes more power than a 250cc engine. What is surprising is that the power difference isn’t greater. The YZ250 makes 45.5 horse-power, while the 80-percent-larger YZ450F makes 52.6 horsepower. That is actually a smaller advantage for the YZ450F over the YZ250 than the YZ250 holds over the
YZ250F (9 horsepower to 7 horsepower).

On sheer numbers alone, the YZ450F will be faster than the YZ250.

Q: HOW DOES THE YAMAHA YZ250 HANDLE?
A: Most MXA test riders describe the Yamaha YZ250 as a stable platform machine. What is a stable platform machine? It is a chassis that doesn’t get in the way of the rider. Unlike a Suzuki, which focuses most of its energy into turning, or a Honda, which dances on a fine line between oversteer and understeer, the YZ250 two-stroke is neutral. Neutral means that you can make it oversteer or understeer by how much input you put into the chassis. It is accurate at turn-in, requires no mid-turn corrections
and self-steers from the center out.

Don’t misread us. The YZ250 isn’t the best handling bike on the track. It is middle of the road at best. But when you combine the “rear-steering” nature of a two-stroke with light weight and snappy power, you get a go-where-you-point it machine.

Q: WHAT DO YOU NEED TO DO TO RACE THIS BIKE OFF THE SHOWROOM FLOOR?
A: Not a thing. You could plop down cold hard cash at 8 in the morning and be racing it at 10 a.m. This baby is race-ready.

Q: WHAT ARE THE BEST MODS FOR THE 2010 YZ250?
A: Here are the top three:

(1) Reeds. MXA test riders choose the Moto Tassinari VForce3 to replace the stock YZ250 reed cage. The Moto Tassinari reed is a simple modification and makes a noticeable difference in the power. Moto Tassinari’s phone number is (603) 298-6646.

(2) Gearing. We also add one tooth to the rear sprocket of the YZ250. Why? Because most MXA test riders want to get into third gear sooner, and the lower gearing punches up the acceleration in second gear (which brings third into play sooner). No matter what anyone thinks, showroom stock bikes are geared for racing—they are geared for general all-around use. Faster riders, featherweight riders and fast tracks work best with the stock gearing.

(3) Exhaust pipe. Two-strokes love expansion chambers, and the YZ250 is no exception. You can get two extra ponies out of the YZ250 with an aftermarket pipe. We typically choose to run a Pro Circuit pipe and silencer because that is what Chad Reed used on his works YZ250.

Q: HOW IS THE STOCK JETTING?
A: Since engine R&D was frozen in place five years ago (2006), Yamaha has had a long development period to iron out the kinks.

MXA’s recommended jetting is as follows:
Mainjet: 178
Pilot jet: 50
Needle: N3EW
Clip: 2nd from top
Air screw: 3/4 turns out (1 turn stock)
Notes: The air screw is very sensitive from 1/2 turn to one turn out. In practice, it doesn’t seem to be as critical after one turn out. If you switch to an aftermarket pipe, you should go up one on the mainjet.

Q: HOW GOOD ARE YAMAHA’S KAYABA SSS FORKS?
A: Awesome. Yamaha has the best showroom forks, because Yamaha engineers decided to turn the age-old position-sensitive damping concept on its head and make their SSS forks 90-percent speed sensitive. Speed-sensitive damping determines damping resistance based on the speed at which the piston moves, not its position in the stroke.

Q: WHAT WERE OUR BEST FORK SETTING?
A: For hardcore racing, these are MXA’s recommended 2010 Yamaha YZ250 fork settings:
Spring rate: 0.43 kg/mm
Oil height: 130mm
Compression: 13 clicks out
Rebound: 14 clicks out
Fork leg height: 5mm up
Notes: On Yamaha’s SSS forks, there is some crossover between the rebound damping and compression damping, which means that turning the rebound in will not only make the forks slower on rebound, but stiffer in compression.

Q: WHAT ABOUT THE REAR SUSPENSION?
A: This is a works shock. It comes with a jumbo-sized 18mm shock shaft, Kashima-coated internals, and a titanium shock spring. This is cool (and something that no other production bike can claim). For hardcore racing, these are MXA’s recommended 2010 Yamaha YZ250 settings:

Spring rate: 4.9 kg/mm
Race sag: 100mm
Hi-compression: 1-3/4 turns out (1-1/2 stock)
Lo-compression: 8 clicks out
Rebound: 8 clicks out

Notes: Yamaha’s high-speed compression clicker (the large dial) is very sensitive to adjustment. Make small (1/8-turn) changes. Use the high-speed adjuster to set the bike’s fore/aft bias at speed.

National speed riders and heavyweight contenders will need to move up to a 5.0 kg/mm spring.

Stoppers: Although everything is modern on the YZ250 brakes, the power leaves something to be desired. Photo by MXA

Q: WHAT DID WE HATE?
A: The hate list:

(1) Updates. We don’t like the idea that the four-strokes get a zillion little updates every year that improve the bikes
in small ways while the YZ250 gets left out.

Q: WHAT DID WE LIKE?
A: The like list:

(1) Ti shock spring. Cool. Very cool.

(2) Frame. The hollowed-out cavities of the YZ250 aluminum frame look cool. Why did Yamaha go away from them on the four-strokes? They didn’t; they just turned them inside-out.

(3) Suspension. You gotta love Yamaha’s SSS suspension—unless you own a suspension shop.

(4) Reliability. The YZ250 could blow up four times before you’d spend as much money as one explosion would cost on a four-stroke. Plus, even if you are the worst mechanic in the world, you could rebuild the YZ250 by yourself with a butter knife and a nut cracker.

Q: WHAT DO WE REALLY THINK?
A: If you aren’t a future AMA Pro racer or a local guy who has a 35-race win streak, you really should be on a Yamaha YZ250. Why? Where should we start?

(1) It weighs 12 pounds less.
(2) It makes more horsepower per cubic centimeter than any four-stroke on the planet.
(3) It starts on the first kick.
(4) It can be rebuilt for lunch money.
(5) It has one-tenth the moving parts of a four-stroke.
(6) It never stalls in a corner.
(7) It sells brand-new for $1000 less than a four-stroke.
(8) You can work on it yourself.
(9) It is the most fun you can have on a motorcycle.
(10) Do you really need another reason?

This entire article was retyped here from a Motocross Action Magazine Test. Please support those who support two-strokes and subscribe to this fantastic magazine.

2010 MXA RACE TEST OF THE KTM 250SX TWO-STROKE

JohnNicholas — Sat, 27 Feb 2010 05:10:59 +0000

It Is A Fast, Lightweight And Agile Bike That is Surprisingly Competitive Against 450s And An Unfair Advantage Over 250Fs

Q: FIRST AND FOREMOST, IS THE 2010 KTM 250SX BETTER THAN THE 2009 KTM 250SX?
A: Yes. KTM has a reputation for making constant upgrades to their bikes. The 2010 KTM 250SX does not obsolete the 2009 model, but it is incrementally better.

Q: WHAT DID KTM CHANGE ON THE 250SX FOR 2010?
A: KTM has more different models of dirt bikes than any other manufacturer. So when they make changes to a new model, the changes can be broken down into two types. First, there are the “brand-specific” changes. These are mods made to every bike in the 2010 KTM stable. Second, there are the “model-specific” changes. These changes are made specifically to the 150SX, 250SX, 250SXF, etc.

Q: WHAT ARE THE MODEL-SPECIFIC CHANGES FOR THE 2010 250SX?
A: There were three KTM two-stroke-only changes.

(1) Cylinder. The 250SX cylinder head has been reinforced for more durability. Aside from the new graphics, the cylinder casting is the only visual clue indicating the difference between the 2010 and 2009 models.

(2) Radiator cap. The 2010 radiator cap has a 1.8 pressure rating. The 2009 250SX used a lower-boiling-point 1.4 rating. This doesn’t make the engine run cooler, but it makes the coolant boil at a higher temperature.

(3) Exhaust pipe. The pipe’s wall thickness has been increased from 0.88mm to 1.00mm to help rock-ding durability. Unfortunately, our expansion chamber was still dinged and dimpled after the first moto.

Q: WHAT ARE THE BRAND-SPECIFIC CHANGES MADE TO THE 2010 KTM 250SX?
A: There were six changes to the 2010 KTM 250SX that were also made to every other 2010 KTM.

(1) Triple clamps. KTM decided more flexibility was in order, so they redesigned the structure of the clamps, switched to two bolts instead of three bolts on the bottom clamp, and changed the offset from 20mm to 22mm (last year the KTM clamps could be switched between 20mm and 18mm positions, but for 2010 they are fixed at 22mm).

Feeling the breeze: The 250SX is 15 pounds lighter than its 450 brother. Thousands of dollars in titanium and carbon fiber doo-dads wouldn’t bridge that gap in weight. This is the lightest 250cc machine built.

(2) Forks. The WP forks have new seals and bushings to reduce stiction (static friction) and sliding friction.

(3) Airbox. KTM’s engineers put a lip around the top of the airbox to reduce the amount of dirt and water that might drip onto the air filter. Additionally, Twin Air designed a new filter for the 2010 bikes, but the old one still works.

(4) Brake pads. All the 2010 KTMs (save the 450SXF) get new Toyo B153 brake pads. These pads are less grabby and more progressive than last year’s pads. Half of the MXA test riders preferred the older pads because they were more powerful.

(5) Graphics. We hated last year’s cartoon graphics. They were too immature for a high-end, high-priced racing motorcycle. KTM has better graphics this year.

(6) Grips. A diamond pattern was added to the Renthal dual-compound grips.

Q: HOW DOES THE 2010 KTM 250SX RUN ON THE DYNO?
A: It’s a rocket ship! This is the most powerful 250cc motocross bike sold. On the dyno, the 2010 250SX made 49.05 horsepower at 8600 rpm and 30.95 foot pounds of torque at 8100 rpm.

For comparison purposes, here is how the 2010 KTM 250SX compares to the Honda CRF250, Honda CRF450 and Yamaha YZ250 two-stroke.

CRF250: The KTM 250SX makes 12.7 horsepower and 11 foot-pounds of torque more than the 2010 CRF250.

CRF450: The KTM 250SX makes 1.8 horsepower and 1.75 foot-pounds of torque less than the CRF450.

YZ250: The KTM 250SX makes 3.5 horsepower and two foot-pounds of torque more than the YZ250.

Q: HOW IS THE KTM 250SX POWERBAND?
A: By two-stroke standards, the 250SX has a very smooth, broad and usable powerband (very linear). The bike has just enough roll-on power off the bottom to glide through hardpacked turns, hook up in tippy-toe situations and help pull the engine into the meat of the powerband. The 250SX doesn’t hit hard down low, but when it comes on the pipe, it makes incredibly strong and usable power through the midrange.

Even though the KTM 250 two-stroke engine hasn’t seen any power improving modifications since 2008, every MXA test rider swore that the 2010 was broader than the 2009. We later discovered that we were running a softer power valve spring than we ran in 2009.

Q: WHAT ARE THE EASIEST WAYS TO CHANGE THE POWERBAND?
A: Before spending money on fancy mods, there are three things to try.

(1) Unplug the wire: There are two ignition curves in the black box. You can switch back and forth by unplugging the connector. In our opinion, unless you want the bike to feel slower, leave it plugged in on the aggressive curve.

(2) Power valve springs: There are two power valve springs supplied with the bike. The stiffer yellow spring, which comes in the bike, has a softer hit and revs through the powerband slower. The softer red spring hits harder and revs through the powerband quicker. We obviously liked the red spring.

(3) Silencer: If you’re ready to spend a little money, big gains can be made from mid-and-up with just a silencer. We have had good results with both the Pro Circuit and FMF PowerCore 2 silencer. We aren’t talking about improvements in decibels, but in horsepower.

Poetry: This simple engine design produces almost 50 horsepower (and that is achieved with 200cc less than a 450).

Q: HOW MUCH DOES THE 2010 KTM 250SX WEIGH?
A: Without fuel, the 2010 KTM 250SX hits the scales at 210.3 pounds. For comparison purposes, the 2010 KTM 250SXF four-stroke weighs 216.1 pounds, while the 450SXF is 230.6 pounds.

The 15-pound difference between the 250SX and 450SXF is huge and can be felt off the starting line, in the air, on the track and when picking up the bike.

Q: HOW GOOD ARE THE TIRES?
A: The old-school Bridgestone M59/M70 tire combo is something we would have chosen back in 1999 (when these tires were new). If we had our druthers, we’d opt for an M403/M404 combo for a better all-around performance package.

Q: HOW’S THE GEARING?
A: The 13/48 gearing complements the broad-feeling powerband and is ideal for carrying speed around fast turns. But most MXA test riders wanted more punch in the middle and swapped the 48 for a 49.

Q: HOW IS THE JETTING?
A: When we would stop and let the bike idle, it would get a little loaded up and feel rich. While riding, the bike ran smoothly. MXA’s recommended jetting is as follows:
Main: 158
Pilot: 40 (42 stock)
Needle: N1EI
Clip position: 3rd from top
Air screw: 1-1/2 turns
Notes: We turned the air screw in one-half turn when we installed an aftermarket silencer.

Q: HOW GOOD ARE THE WP FORKS?
A: Although KTM has taken little steps in the right direction every year, the WP forks are still a mystery. For some reason, the 450SXF forks are good, while the 250SXF forks are terrible. As you would expect, the 250SX forks fall somewhere in the middle. In the past, the MXA wrecking crew would lower the fork oil height by 20cc to lessen midstroke harshness. Unfortunately, KTM lowered the fork oil height 20cc on the production setting (without lessening midstroke harshness). We opted instead to run stiffer fork springs to hold the forks higher in their stroke (and also because the stock 0.44 springs are lighter than the springs in the 250SXF four-stroke)

Q: WHAT WERE OUR BEST FORK SETTINGS?
A: For hardcore racing we recommend this fork setup on the 2010 KTM 250SX:
Spring rate: 0.48 kg (0.44 kg/mm stock)
Oil height: 360cc
Compression: 7 clicks out (12 stock)
Rebound: 12 clicks out
Fork leg height: 5mm up
Notes: Thanks to new seals and bushings, the amount of stiction has been reduced (previously the WP forks had excessive static friction). If you switch to a firmer shock spring (which we recommend), the bike would be better balanced with the 0.48 kg/mm fork springs as well.

Q: HOW WAS THE WP PDS SHOCK?
A: KTM switched to a stiffer shock spring last year, and this year we decided to switch to an even stiffer shock spring (something we learned from working with the 450SXF). So, faster and bigger test riders went to a stiffer 7.6 kg/mm spring, but most opted for the 7.2 spring off the 450SXF. The stiffer springs required less preload, the WP shock felt free in the first part of the stroke and worked well through high-speed bumps. If you weigh less than 175 pounds, stick with the stock shock spring.

Pucker power: This Brembo/Galfer/Toyo combination is very powerful, yet easy to control. This is an awesome front brake.

Q: WHAT WAS OUR BEST SHOCK SETTING?
A: For hardcore racing we recommend this shock setup for the 2010 KTM 250SX:
Spring rate: 7.2 or 7.6 kg/mm (6.9 stock)
Race sag: 110mm
Hi-compression: 1 turn out (1-1/2 stock)
Lo-compression: 19 clicks out (15 stock)
Rebound: 15 clicks out (24 stock)
Note: Race sag can vary from 100mm to 110mm.

Q: HOW DID THE 2010 KTM 250SX HANDLE?
A: This isn’t your father’s four-stroke. It is amazing what a two-stroke can do that a four-stroke can only dream about. As a rule, all four-strokes take the same line because they are trying to maximize their torque advantage. Not so with the 250SX! Test riders could go wherever they wanted. They could cut across the inside of corners, go way outside in sweepers or jump out of ruts halfway around a bend.

Thanks to the lightweight and rapid throttle response, a KTM 250SX rider can change lines, pivot on a dime, hop out of ruts and take shortcuts that 450s couldn’t get to if they tried.

The downside of this agility is that any wheelspin can cost you drive.

Q: WHAT DID WE HATE?
A: The hate list:

(1) Gas tank. MXA hasn’t liked black plastic gas tanks since they were first introduced. And we don’t think that KTM’s engineers like them either, because for 2010 the XC models get semitransparent gas tanks. We want to know how much gas is in our bikes, too!

(2) Forks. WP has the potential to make great stuff, but WP’s setup has been hit and miss. Some models work well, while others stink. The 250SX forks are somewhere in no-man’s land.

(3) Handlebars. They are too low. Usually, the MXA test riders would just throw the stock bend away and mount their favorite bar, but this year we opted for the economical choice and got taller bar clamps from KTM’s parts catalog. These were about $25 versus handlebars at about $90.

Q: WHAT DID WE LIKE?
A: The like list:

(1) Brakes. When you add the dynamics of a 260mm Galfer rotor and the 250SX’s light weight, you can out-brake anyone on anything (except a KTM 150SX).

(2) Horsepower. KTM knows how to build engines. This is the fastest 250 two-stroke made.

(3) Psychological warfare. Most racers are accustomed to the low-pitched drone of thumpers behind them. Surprise! They find a shrieking two-stroke behind them nerve-wracking. We used the sound of the the KTM 250SX to disorient the guys in front of us.

(4) Hop-ups. Compared to its four-stroke brethren, the 250SX is an inexpensive bike to maintain and to hop-up.

(5) Sound. Under AMA rules, a 250cc two-stroke can make 96 dB, while a four-stroke can only make 94 dB (because the sound of a four-stroke carries twice as far as two-stroke sound). The KTM 250SX produced 94.5 dB, which is quieter than most four-strokes.

Q: WHAT DO WE REALLY THINK?
A: The box-stock 2010 KTM 250SX is a fast, lightweight and agile bike. It is surprisingly competitive against 450s and an unfair advantage over 250Fs. It is inexpensive to maintain and simple to work on. If the KTM 250SX doesn’t make you rethink the four-stroke revolution, nothing will.

2010 TM 125 MX – First Impression

JohnNicholas — Sun, 10 Jan 2010 16:44:31 +0000

Unlike the major manufacturers, TM Racing is not resting on their laurels for the two-stroke market. TM continues to improve their machines to ensure that racers have choices.

The look, fit and finish of the TM is reminiscent of a factory works bike. Only the very best parts and components are used to build the TM racers.

The attention to detail that TM lavishes on their machines is not limited to the obvious flashy bits and pieces. TM Racing builds their own proprietary frames, swing arm, triple clamps and billet hubs. Plus there is an excellent reason for every component that TM sources for their machines, they much live up to the rigors and abuse of racing.

TM’s are not very well-known in the USA. There are a few reasons for this, but mostly because the TM Racing factory decided to limit the yearly production of TM’s. Over the past decade or so, there have been quite a few different distributors in the USA and their efforts were not well-received.

Up until now. Up North in Canada there has been one distributor for TM Racing over the past 10 years, Barker Bros. Cycles. The head of Barker Brothers is Dan Barker who has a passion for these machines that is second to none. For 2010 and beyond he has been granted the rights to distribute the bikes in the USA.

Dan has put together a team of associates in the USA to help him get the bikes in front of the off-road motorcycling public. He has supplied these associates with brand new 2010 TM Racing machines to be shown to and tested by interested racers.

This unusual test ride arrangement is outside the norm for any manufacturer. But as Dan Barker observes, how else could interested folks make a decision on which bike was best without getting to ride it?

I know which way I’d prefer to make a decision.

One of the folks that Dan has entrusted with a brand new 2010 TM Racing machine was us here at Two Stroke Motocross. We have a 125 MX model for those on the East Coast to test and try out for themselves. If you’re on the East coast and want to set up a test ride, please contact Dan, and we’ll do our very best to accommodate you.

In order to bring you an unbiased test impression of the machine, you will not hear my opinion on this machine. This is done for a few reasons, but mostly because I have a “vested” interest in this machine. This would be unfair to you the esteemed readers of this web site.

I have dedicated many hours of my personal time to bring you the truth as I’ve found it. By giving my opinion on a machine, especially when I could benefit from it, would be against everything I believe in. And what I’ve considered an unfair practice from the rest of the mainstream motorcycle media and industry.

You should have the opportunity to make your own decision based on un-biased testing.

To that end I secured the help of some of my racing friends to test the bike. None has taken to this idea to heart as much as Mike Leavitt. Mike is an extremely talented Pro racer from the local area who has a great deal of racing and testing experience.

When I mentioned that I would be getting a TM Racing machine, Mike was very interested in testing it. We set a date to take the bike to an indoor arena for initial testing. What I didn’t know is that Mike had invited his friend Paul Sanders from IV Films to shoot video of the bike and ask Mike some questions.

Here are the results of Paul’s work…

There will be much more testing in the future, with feedback from many other people. This will allow you to decide if a TM Racing machine is for you. Of course if at all possible, I suggest you test ride one for yourself before making a purchasing decision.

From the impressions from the other racers that tried the machine out, this is an expert style machine. It responds well to a heavy throttle hand, aggressive racing and tap dancing on the shift lever. At least that is the impression of the 125 two-stroke.

When new, the suspension is stiff and needs to be adjusted. It is very sensitive to small clicker adjustments, so take your time, make the changes and test again.

A few testers expressed an uneasiness with the feel of the machine. Noting that the front end felt like it was “under” the bike, giving it a stink bug feel. These impressions were made before many adjustments were made to the machine. Mike felt that the sag needed to be lowered, so we borrowed some tools to adjust, which made a significant difference.

One test racer, Devin, took a couple lap test. He currently races a YZF250, but owns a 2005 KX125 which has a full Pro Circuit motor. He felt that the stock TM was way faster than than his modified KX.

Don’t let marketing hype, paid advertisements or riding impressions by people that have a vested interest in selling you something. Get information based on testing from people you know, trust and from your own experience.

Just something to keep in mind when basing purchasing decisions on other racers. What bike do they currently ride? Two-stroke? Four-stroke? What brand machine? What size? Who are they sponsored by? What are their preferences? What is their skill level? Does any of this stuff match you and your riding ability? This could make a huge difference as to whether the testers experience will mean anything to you, please don’t take this lightly.

Honestly yours is the only opinion that counts!

Photos of the bike are located here – http://tmracingmotorcycles.com/media/photos/

Transworld MX Service Kawasaki KX500AF Test

JohnNicholas — Tue, 22 Dec 2009 16:54:52 +0000

Back when men were men and motocross bikes were faster than they needed to be, 500cc two-strokes ruled the roost-no pun intended. In the heyday of motocross, names like Jeff Stanton, Ricky Johnson, Mike Kiedrowski, and Mike LaRaocco were the stars aboard these blistering fast machines, competing for the once coveted 500cc National Championship. Since then, however, times have changed, as four-strokes have rapidly become the dominating machines in both professional and amateur competition around the world.

Due to the simple fact that the new four-stroke technology has taken over, two-strokes have gone the way the way of the Dodo for most manufacturers, and to quite a few riders, are all but forgotten memories of motocross’ past. Thankfully, though, for all the diehard premix fans out there who want to go ridiculously fast, Service Honda has come to the rescue with the new Service Kawasaki KX500AF. Packing quite a punch, and squeezed into a 2009 KX250F frame, the KX500AF is without a doubt, an interesting bike.

Brendan Lutes on the KX500AF.

THE BIKE
Service Honda has long been know for… you guessed it, squeezing Honda CR500R motors into modern aluminum framed chassis, but up until this year, the company hasn’t ventured into producing a bike based on the KX500.

Through a special agreement with Kawasaki, Service Honda uses brand-new components to build each KX500AF. To begin the project, Service Honda takes a stock KX250F and strips it down, cutting the frame and welding new down spars in place to hold the powerful KX500 motor. From there, the motor is slipped in while all the necessary components are mounted up to complete the bike. When everything is said and done, the KX500 motor fits flawlessly into the KX250F chassis. A few of the custom features that make up the KX500AF include custom front airbox plate for optimum airflow along with a new airboot, a stainless steel clutch cable for increased life. a works-style aluminum skid plate, and a 39mm Keihin PWK carburetor to feed the motor.

As far as suspension is concerned. Service Honda recommends getting it revalved by MX Tech Suspension in order to handle the new characteristics of the powerful KX500AF. When we took delivery of our test bike, the first thing we did was mount up massaged suspension-although from Pro Action rather than MX Tech-off of our KX250F test bike, giving the 500 the highly recommended upgrade. Other than that, our KX500AF was left largely untouched from the condition and setup that it was delivered to us in.

OUT ON THE TRACK
The Service Kawasaki KX500AF is a very powerful bike that demands respect from anyone that swings a leg over it-the power is instantaneous and awesome. Out on the track, the low-end grunt is something that one has to feel to believe, and once the throttle is cracked, it comes on strong, pulling very hard into the upper portion of the powerband. It pulled so far that even on fast tracks we struggled to find where the power signed off. Compared to other two-strokes we have ridden in the past, the 500 has more of a tractor-like powerband. While the power is very strong, it is strong in a different way, allowing some control over what most would think to be an uncontrollable experience. On the other hand, though, this power can be deceiving, as it builds up and continues to pull forever.

We haven’t ridden an original KX500 since, well…. we don’t remember, so it’s kind of difficult to comment on the vibration of the Service bike compared to the old chassis, however we can say that the vibration of the KX500AF isn’t bad. While it does vibrate a little more than a four-stroke, it isn’t enough to make for an unpleasant ride, but rather enough to wear you out quicker than normal. The 500 is a potent bike, and because of that, it’s going to wear the rider out a little more. Having said that, however the Service bike is much more nimble than we had expected before riding it. The lightweight 250F chassis provides a very modern feel to the ride, while working well with the powerful 500cc engine, giving the bike a controllable feel despite the big motor. As for the suspension, we swapped out the stock suspension in favor of Pro Action suspension and the end result was excellent.

The bike never felt nervous at speed down straights, and was very confidence-inspiring over jumps. As for smaller hits-braking bumps and acceleration bumps-the forks and shock worked very well to keep the bike riding straight. Simply put, if you like the handling characteristics of the KX250F, you’re going to like the way the KX500AF handles after a little suspension tuning.

WHAT WE THINK
Our time aboard the big green Service Kawasaki KX500AF was a blast. Before riding it, we had our questions about whether or not it would perform up to par, but after testing it in races and at various local tracks, we have come away surprised with how well it works as a complete package. One thing is for sure though, in spite of the new chassis and ergonomics, the KX500AF remains a true “man’s” bike, as the brute power is something that can’t be taken lightly, not to mention holding on for an extended period of time requires more training for the truly dedicated. For everyone else, it’s a lot of fun no matter what.

There’s No Replacement For Displacement

By Brendan Lutes
Up until the time when the Service Kawaski KX500AF arrived at our offices, I had only swung a leg over a 500cc two-stroke once in my life. I always thought that the fabled bikes of yesteryear would be way too much to handle for anyone, and that for me, I wouldn’t be able to ride to my full potential. I couldn’t have been more wrong.

After getting used to the KX500AF and pounding out a few motos, I became aware that although the big bike commanded a lot of respect, it was a bike that was very fun to ride. The instant power allowed me to ride around the track and be lazy-I’m not sure if that’s a good thing or not-and the lightweight chassis that the motor was placed into gave the bike a feeling reminiscent of the modern four-strokes I have become accustomed to. While I did get tired much quicker, it wasn’t something that I couldn’t overcome with a little more seat time aboard the big bike, or a little more time at the gym rather than my favorite watering hole. In fact, since taking delivery of the KX500AF, I’ve even raced it and had a blast. But riding motos on it is one thing; where the test really got interesting for me was when we broke out the stopwatch.

After being timed aboard the big KX500AF at Racetown 395, I hoped on my more familiar KX450F and immediately felt right at home. While pounding out timed laps, I clearly remember thinking to myself, “Man, I’m killing the lap times I set on the 500!. Upon pulling back into the pits, however, I found that I couldn’t have been further from the truth. While I felt faster and more at home on the 450, my lap times on the 500 were consistently two to three seconds a lap faster. In the end, the truth of the matter was that the brute power of the 500 undoubtedly allowed me to carry more speed down the straights and through the corners-even if it didn’t feel like it-giving the big bike that little edge over the 450. Even though the lap times speak for themselves, under race conditions, and on a rough track, I would probably pick the 450 over the 500. I’m more comfortable on the 450, and I can ride it at a consistent pace for a longer period of time. Nonetheless, I still had a blast during my time testing the 500. It’s definitely something different and fun.

2004 Maico 500 Long Term Test Report – Part 2

Big Bore Maico — Wed, 16 Dec 2009 04:49:32 +0000

Establishing a Baseline
It has been said: “Opinions’ are like belly buttons…everyone has one”. I am inclined to believe that there are folks out there who have a pocket full of belly buttons! It’s great to have differing opinions. I always enjoy exchanging thoughts and opinions with those who have based their positions on FACT.

Just because we have differing opinions doesn’t infer that one is correct and the other incorrect. Unless of course, that opinion is based on conjecture, speculation, bias or even (yes I will say it) IGNORANCE. I say these things because what you are reading are MY OPINIONS of a motorcycle. And these opinions are based on more than feelings, affection, brand loyalty or speculation.

For clarity and intellectual honesty, I will take the time to address my background. And I do this because my background has a direct influence on my opinion, and the reader deserves complete transparency, honesty and TRUTH (as I see it).

I don’t own stock in Maico, nor do I own a Maico dealership (nor have I ever been in either position). I am not being compensated for this in any way, from any one. It is my hope to bring the enjoyment and freedom of riding a motorcycle (particularly the Maico 500) to anyone who cares to do so.

With the explosion of “information” available on the internet, the fact that this information is neither peer reviewed nor vetted by an editor, and virtually anyone with a computer and internet connection (is anyone not connected??) can post on virtually any subject, the reader MUST do these things for himself. Do you know the background of any of the “test riders” of the various magazines? Some are ex-pros. Yet we know very little about them.

We know even less about those who post on the internet. A sad testimony to the sport of motorcycling today is the lack of objective, unprejudiced testing. Anyone who thinks that advertising dollars do not play a significant role in the outcome of your standard motorcycle “shootout”, you are mistaken. I have lost count of how many different people have told me that very thing. Would these people say these things to the general public? Never. It comes off as arrogant, whiney and controversial. But that does not negate the truth that advertising dollars influence the outcome of tests.

There are many ways to better form your opinions other than magazine “shootouts” and internet articles (including what you are reading now). And that is to ride as many DIFFERENT bikes as you can, and base your choices on that. Do not use what I say as the canon (measurement) of truth. Ride, ride, RIDE.

Motorcycling, like any other field of endeavor, is filled with crooks, posers, blowhards and riff raff. They have their agenda, and most likely, it is to fill their pockets with YOUR money.

The easiest account of this is the modern four stroke dirt bike! It was going to save motocross, trail riding and the environment, all while causing you to be a better rider. Great marketing, but has this proven to be truth? Not in my book. It has escalated the cost of racing to NASA levels, reliability is in the toilet and the sound levels of these machines is causing riding areas to drop like the stock market. I’ll stop on the four stroke thing for now (or I won’t stop).

Probably the most interesting of the above noted group is the “posers”. They want to be in the “in” crowd. They read all the magazines (also known as “comic books”), know the entire “lingo”, but can’t tell a spark plug from a screwdriver. Sadly, this makes up the better part of dirt biking today. These people are quick to point out the blatantly obvious, quoting tired, worn out talking points from the media. They have virtually zero practical experience, but are sure they are correct.

I mention all these things because I am NOT a poser, a faceless drone hiding behind my computer screen. I have spent the better part of my entire life in and around the motorsports business, in various degrees. If you think politics is a dirty business (and I think it is), motorsports rivals the political arena in every aspect. I am a machinist by trade, and I have spent countless hours trying to coax every single bit of power from internal combustion engines.

Since 1980, most of that time was spent on multiple cylinder four stroke engines. That’s right, FOUR STROKES. This puts me in a unique position to be able to speak on the shortcomings of the “modern” four stroke. I have owned my own flow bench, spent countless hours “on the dyno” and more days and nights at the track than I care to remember. Again, my background is that of one who is in the day-to-day business of motorsports. I have access to industry “people” that the average person just can’t get to.

I remember being told the four stroke was making a comeback in dirt biking. I laughed. I had forgotten that derelicts are in charge of the AMA. It had slipped my mind how corrupt the “major” factories are. I completely lost my mind on the fact that motorcycle magazines exist for one reason and one reason ONLY: to sell YOU the products and services THEIR advertisers produce, whether or not you need them. Between them all, they re-wrote the rule book, re-designed the race tracks and sold the off-roading public a sham.

I have been around the block, taken to the cleaners by customers and manufacturers alike. The sad fact of the matter is this: the industry won’t change unless it is through force (meaning the pocket book). Stop attending motocross and supercross races, don’t buy Dirt Bike, Dirt Rider, MXA et al. Don’t spend your money with those manufacturers who cater to the four stroke side of dirt biking. Speak with your wallet, and then email all those folks and tell them why you stopped blowing your cash to uphold their corrupt institutions. Now that all that is out of the way, lets discuss the mechanical aspects of Maico motorcycles.

Nuts and Bolts

The overwhelming complaint I have heard of the Maico is that it is “old school”. Most complain about the “dated” plastics and steel frame.

Let’s discuss the steel frame first, as it is entirely more relevant than “bold new graphics”. I had been away from dirt biking for the better part of 20 years. In 2002, I decided it was time for fun, as building racing engines (and dealing with all the associated garbage that goes with it) was becoming quite the hassle. I decided that a dirt bike was the answer for stress relief. Imagine my shock when I looked around and noticed an aluminum framed dirt bike!

To say I was stunned would be a gross understatement. For the life of me, I could not understand this strange anomaly. Yet today, it is taken for granted that an aluminum frame is requisite for a competitive dirt bike. I completely disagree. I asked anyone and everyone about this “new” frame. I didn’t get the full answer right away. It has taken literally years to piece together what actually happened. And, as I would have guessed, the switch to aluminum frames was not necessarily to benefit the end user (as it is with many “new” things).

Dirt Bike magazine published an article on a Japanese motorcycle show. I have forgotten some of the details, but the facts remain the same. In a 1 or 2 line blurb, Dirt Bike admitted to“knowledge” of a shortage of “quality” steel in Asia. So here is our first big clue! Market shortfalls are common, especially in times of war or other “artificial” factors. All of Asia was (and still is) experiencing a shortage of quality steel. This shortage does several things. It makes costs for materials to go up. It also makes the bean counters look for “alternative” materials and techniques to save money, and keep the cost of the product you are trying to market stay competitive.

The average consumer has only “so many” dollars he can spend on hobbies. If the manufacturer can’t keep costs in line, they lose market share. So we see that the first reason for aluminum frames was and is a steel shortage in Asia. Next comes the marketing department. They need to make the end user (that’s YOU) think that this “new” design or product is absolutely required for your success.

Can you imagine any of the “big” manufacturers telling you they made a design change because of materiel shortages or to make production go quicker, thereby reducing costs? They are going to use advertising to convince YOU that this was needed for your success. So the Asian manufactures switched to aluminum frames because resources REQUIRED them to do so, but told the public a different story. This is also a text book example of how and why advertising works. Let’s compare steel to aluminum as a structural materiel and see what we find.

Steel has a higher stiffness to weight ratio than does aluminum. To achieve the same structural rigidity, the cross section of aluminum MUST be greater. This should be obvious to even the most uninterested observer. Look at the overall size of the structure of your aluminum framed dirt bike. Where a 1 inch round tube (4130 chromoly steel) will be sufficient structurally, aluminum requires almost 3 times the cross section to achieve the same rigidity!

Aluminum twin spar frame.

Just put a steel frame and an aluminum frame side by each. Stevie Wonder could see the difference. This greater cross section does nothing more than take up valuable space and makes it much more difficult to do maintenance on. Aluminum also has another not-so-desirable character. Aluminum work hardens at a much greater rate than steel. You may not know it, but dirt bike frames flex, twist and bend. During this process, everywhere these actions occur, the possibility of fracture greatly increases (think of bending a paper clip).

Aluminum does not hold threads as well as steel, so the possibility of stripped threads is much greater (especially if you are naturally ham fisted and use 1/2″ drive tools), and therefore the required repair.

As a general rule, aluminum welding is done using what is known as the TIG process. Steel can be readily welded using the MIG process. A MIG machine is more likely to be found in most home shops. MIG welding is a much faster process, is a simpler process and is done by most folks at home. The general public does not usually own a TIG welder. Most own a MIG machine. You CAN weld aluminum with a MIG welder, but it does not do as nice a job as a TIG machine does.

If we consider all things here, the only upshot to an aluminum framed dirt bike is the marketing department. Again, these are facts, and coupled with my opinions and life experiences, I still won’t own an aluminum framed dirt bike. Once again, the buying public has been duped into something they didn’t need. Market shortfalls and tricky advertising have the public fooled.

There are still some manufacturers who build steel framed dirt bikes. Maico, Husky, Gas Gas and KTM come to mind. A steel framed dirt bike will corner, jump, ride and stop as good as, or better than its aluminum framed counterpart (providing frame and steering geometry are equal). So, when weighing your options for a new dirt bike, rise above the marketing department, ignore the experts at the various magazines and base your decision on YOUR riding experience.

CR250 steel frame.

So what about all the raves over aluminum framed dirt bikes? Pay very close attention to who is telling you about it. Chances are they just jumped off their clapped out, never maintained, ridden hard and put away wet bike. I’ve seen bikes with bent foot pegs, original oil in the forks and shock, never serviced the rear suspension linkage etc and this is the guy who raves the loudest about his “new” aluminum framed bike. And we all wonder how this is. I have witnessed this exact scenario so many times I’ve lost count.

Also, some of the raving can be attributed to better geometry. Let’s face it. A 1980 anything won’t have the same frame and steering geometry as a 2008 bike. You are comparing apples to cabbage. So it’s a package deal. Improvements in suspension allow for changes in geometry. As tires improve, chassis design can be modified to exploit the improvements.

As for the plastics…I personally have a hard time getting my mind around what the complaint really is. I can get plastics in virtually in color I want, from a variety of sources. It amazes me that grown men complain of such a petty issue as this. Reminds me of a woman who can’t buy something because it doesn’t match her purse. But there is a whole industry based on graphics to make your bike “look” like a factory bike. I would rather spend my money on something that actually improves performance or reliability. Or use that money to ride more. But that’s just me. Now let’s move on to things of greater concern.

2008 Maico with Reiger shock.

Let’s talk about suspension. Prior to 2005, all Maico’s came with WP 50mm Xtreme conventional forks. Again, these fall under the heading of “old school”. But I did my homework. If you can find an honest suspension guy (I have a great one) he will tell you the benefit of upside down forks are little if any over conventional forks. 2005 and later model bikes are getting USD forks. Other than being slightly heavier (5-7 pounds), the Xtreme will do 99% of what any rider can want or need.

Some of the bikes come with an older WP shock, and some come with a Reiger unit. I’ve never seen the Reiger (except in pictures) but they are said to be a great piece. If I had my say, I’d get the Reiger. The WP can be made to work with regular suspension tuning. I have never seen a bike come off the showroom floor with the proper spring rates and valving for everyone. It’s not a one size fits all proposition. Bad suspension breeds bad riding habits. Again…graphics or suspension work? For me it’s a no brainer.

That’s why race teams employ full time suspension tuners. That’s how critical it is. Sadly, most guys don’t even adjust the clickers (and many don’t know how to do it or understand what they are doing). The marketing department says “our bikes are suspended for mid level 160 pound riders”. I don’t ride with anyone who fits those criteria. Regardless of what you ride, if you haven’t had your suspension customized for your weight, ability and type of riding you are leaving performance on the table.

You will find those who proudly tell you they have never adjusted the clickers and the bike is perfect for them. They are either stupid or lying. I always pay close attention to those guys when I ride with them. They have poor form (sit down way too much, feet off the pegs, rarely or never use the front brake), or as they ride the bike beats them to a pulp. Ignore these types. Unless you enjoy watching your friends (or enemies) spend their day picking themselves up off the ground (yes, I enjoy watching Spodes fight their bike all day then tell you how good a ride they had).

Another complaint I have heard of the Maico is the swing arm. It’s too heavy…too bulky. They speak from ignorance. If anything, it’s too light. There is a brace running from side to side, between the shock and the swing arm mounts. It WILL develop a fracture.

For one thing, the brace is cut too short. Second, they slobber weld on it to fill it in. To fix this, you have only two options. Your first is to slobber more weld in there and hope you handle it. The second is the correct way to fix it, but it is much more labor intensive. If mine fractures again, this is how I will do it: you cut out the existing piece. Then you bore holes THROUGH both sides of the swing arm. Using heavy wall tubing, slide the piece through the swing arm and weld both inside and outside. This will stiffen the swing arm and prevent future fractures. Come on Maico, this is just bad workmanship. I wouldn’t put my name on that. I apologize for the poor quality photos, but it’s the best I have.

Typical needle bearing.

While we are here at the swing arm, let me complain about another pet peeve I have. Any second year engineering student will tell you not to put needle bearings on a reciprocating shaft. Maico has followed the industry in this error. Needle bearings need to rotate. They don’t like to be beaten on. And they really don’t like to be hammered on while they are reciprocating.

If you look closely at the photos, you will see I have machined BUSHINGS to replace these idiotic bearings. Again, it’s cheaper to manufacture needle bearings than bushings. They both require the same amount of maintenance. Bushings have much more bearing area than needle bearings. So whenever the opportunity brings itself to me, I swap out bearings for bushings. Thankfully, Maico still uses bushings in the shock linkage. Bearings have an even shorter life span in the linkage than they do in the swing arm itself.
Engine Components

One of the great aspects of Maico motorcycles is in their SIMPLICITY. Complication equals frustration. It’s just about a sure thing that when you make something more complicated, you have increased cost, decreased reliability and added weight and gave form over function.

All Maico’s come with Magura hydraulic clutches. Once you ride a bike with a hydraulic clutch, you will see the foolishness of cable operated clutches. I know, the pros complain they can’t adjust the clutch on the fly for “feel”. Anyone racing a KTM has a hydraulic clutch, and I’ve never heard any complaints about it (once they get used to it). This adjusting for “feel” is nothing more than compensating for clutch wear and heat. Nothing trick here. This is one of those exceptions where complicated is BETTER.

But when you look closely, you will see it’s actually no more complicated than a cable operated clutch. The cable is replaced by a hose. The arm on the case is replaced by a slave cylinder. You have a master cylinder on the clutch lever. The only excuse to NOT have a hydraulic clutch is that the bean counters won’t cough up for it. They will give you dual mufflers (Honda 250F) but not a hydraulic clutch. It’s not flashy, and it’s hard to market. To spend the money for a new bike and not get a hydraulic clutch (in my OPINION) is senseless.

There is one hang up though. Maico designed their own slave cylinder, instead of using the Magura unit. I’ll tell you straight up…the Magura slave cylinder is good, but the Maico piece is better. I know this because my 2004 came with a Magura slave cylinder, and my brothers 2003 has a Maico piece.

I emailed the factory, and to their credit, they gave me the straight poop. Maico is a small manufacturer. Sometimes a casting comes out of the mold without the boss for Maico slave cylinder. Sometimes, while machining the case, the boss gets machined off. Instead of throwing away the case, it is machined flat for the Magura slave cylinder. I was told this only happens with 500’s, and not with other displacements. The Maico and Magura slave cylinders are not interchangeable. So to save the case, Maico will machine the case to take a Magura slave cylinder. This is the same unit that came on 125 and 200 KTM’s. There is little difference in function between the Magura and Maico slave cylinders. The Maico is easier to maintain, doesn’t require gaskets and is slightly smoother.

As far as internal pieces go, most pieces interchange with earlier Maico models. The crank halves are 500 Maico, and the crank pin, the piston, wrist pin, wrist pin bearing and rod are 490. The crank pin is slightly outboard from a 490 to make up the 10 cc difference in displacement. Even the reeds are early Maico and can be easily purchased. The clutch is the same as 1986 and later models. Why update? It’s simple, doesn’t slip and works.

One of the updates that comes on 1999 and later models is a removable inspection cover for the clutch. Maico lowered the engine in the chassis and you would not be able to service the clutch with the engine in the bike. Again, here is an update you can’t really see (lowering the engine in the chassis) but is an important one no doubt. Maico’s come with a compression release. Once you get the hang of the left side kicker and using the compression release, starting the Maico is a snap. Maico uses a power valve in the exhaust (KX 500’s have one, CR 500’s do not). This simple device broadens the power curve. Why not have one?

If you get an enduro, model you get lights, S.E.M. ignition, an 18 inch rear wheel and Bing carburetor. If you get the MX version, you don’t get lights (I can’t understand the riding a dirt bike at night thing) but you do get a PVL ignition, 19 inch rear wheel and Mikuni TMX carburetor. There are NO OTHER DIFFERENCES. So let’s discuss the differences you do get.

The difference between the 18 and 19 inch wheels for 99.9% of us is basically nothing. The only problem I see with 19 inch wheels is getting a wide enough tire. Other than that, I don’t care. The S.E.M. ignition is a great piece. Reliable, simple and it will run lights. That’s all I can say about it. One of the reasons I hate 4 strokes is they rev very slow. The S.E.M. ignition is of the external rotor type. Being external rotor, you have an incredible flywheel effect. I don’t like that.

I grew up riding MX bikes in the woods, so I learned to live without flywheel weight and learned the art of throttle control. You can’t add or remove weight from the S.E.M. The PVL is an INTERNAL rotor ignition. The difference between the flywheel effect of the two ignitions is substantial. The real difference is that with the PVL you can get several bolt-on flywheel weights, and use them at your discretion. So if you are riding in slimy, sloppy conditions, you can put on 16 ounces of weight and slow the ability of the engine to rev, thus increasing available traction. Then remove it when the conditions are more favorable. Or maybe you are going to ride some tight single track. Add 12 ounces of weight and it will help keep the engine from stalling in corners. It just gives you options for tuning.

If you MUST have lights, then you need the S.E.M. Some of the bikes are coming with single stage, fiberglass reeds, and some are getting dual stage fiberglass reeds (Boyesen). I have spent more time than I care to remember dinking with reeds, single stage, dual stage, stainless petals, carbon fiber and many different combination’s of some of these components. I learned a lot. First, I am not nearly as smart as Mr. Boyesen. I have talked with him on the phone, at length, and he is intelligent beyond words. He explained things to me in a manner that I can understand.

Second, when all is said and done, the dual stage, fiberglass reed system is far and away the best set up for all around two stroke performance you can get. I hate to endorse a product without compensation but, I have tried it all and came back to this. I also learned that as you get larger in displacement, the disparity is greater. The 500 is entirely more sensitive to reed materiel and design then a 250. So, when you get your bike, pop the carb off and see what you have. If they are not Boyesen style fiberglass reeds, drop the dime and get them.

TMX Mikuni Carburetor.

I could write a book (and maybe I will) about tuning two stroke performance engines, and the TMX Mikuni is the biggest piece of garbage I have seen. Maico should be ashamed for selling a bike with this untuneable piece of junk on it. The Bing is far superior (here come the arguments) to the TMX if you come at it with an open mind. The Bing responds to tuning changes better and is just manufactured better.

The TMX has pressed together parts in it, and the circuitry is flawed. But the media has had a problem with the Bing for years and so does anyone who has not tried one. Funny thing is, I can tune a Bing, but all the gurus at the different magazines can’t. Follow the money here. Ultimately, I prefer the Keihin carburetor. It is the simplest to tune, and is more sensitive to adjustments. If Maico wants to improve things, lose the TMX and put a Keihin on it. Ultimately, the do-all, be-all, end-all would be a three circuit carburetor. They are available, but they are expensive. I own one. I would NEVER go back. If people understood how to tune 2 stroke carburetors, you wouldn’t need direct injection (in my opinion).

As far as other parts and pieces go (like sprockets etc.) they are readily available. Brakes are Brembo, so KTM, Husky, Gas Gas, Husaberg, and even VOR pads fit. Levers are Brembo (front brake) and Magura (clutch) and available at the same places. The front sprocket is KTM and the rear is the same as 86 and later Maico’s. They are available through PBS, Sprocket Specialties and about any other manufacturer. My bike has Akront rims and they are every bit as good as Excel.

While I’m on this point I want to hit on parts availability. Yes, you are correct. Maico dealers are not on every corner. But this is the NEW world, a “global” society. Guys now buy parts all day (and night) ON LINE!!! In a few days the brown truck (and others) pull up and bring the parts to your door. I can’t tell you how many times I needed parts for a Japanese bike and had to ORDER them!! Even though the dealer was within walking distance I STILL had to wait. In my life I have owned many different European bikes and I never EVER had a problem getting parts. It’s 100% MEDIA driven. Shame on them for being so underhanded. But that’s a different story for another time.

So there you have it. A simple run down of a Maico motorcycle. They are so simple that it’s funny. Liquid cooled, reed valved and having a power valve in the exhaust what more could you ask? They come with HGS exhaust, and the pipe is dimensionally similar to an FMF fatty. It’s nickel plated, so it looks nice too. Seat covers and graphics are available from the factory, but they are a bit pricey. And if the General gives me the space, I’ll do part 3…what it’s like to RIDE a 500 Maico! And with any luck (and a Mac computer) I’ll include video.

Never forget…REAL MEN PRE-MIX. Always have, always will.

2004 Maico 500 Long Term Test Report – Part 1

Big Bore Maico — Wed, 09 Dec 2009 01:39:35 +0000

I was asked by “The General” to write a long-term test for the Maico 500. I own a 2004 Maico 500 and my brother owns a 2003 Maico 500, so I have a good idea of these bikes and a very good feel for them. I’ll do my best to give as many details possible.

The test report will be broken into three parts. The first part will deal with the bike itself. This will include everything from ergos, assembly and construction, the various things that make the Maico a Maico. Part two will be an in-depth look at the mechanics of these bikes. I have been through every part of these bikes and I’ll tell you everything I’ve found. In part three, I will cover of the most important part of the entire article. I will report what it is like to ride the Maico.

My goal is to inform you, not to convince you that you need a Maico. Just for the record, a Maico is not for everyone. For those who wish to ride an open class two stroke, with European handling, then it’s worth your time to investigate the Maico.

The first thing that you will notice when you see the Maico in person is how tall it is. The Maico has one of the tallest seat heights in all of the industry. You’ll also notice that the Maico has a steel frame (I’ll cover my thoughts on this later). As you look over the bike, you will notice that everything is the grandest in size. The cylinder itself dwarfs that of a 250 two stroke. A friend once commented that the cylinder looks like something from “Sputnik”. It has a right side chain drive, and a left side kick.

You’ll also notice that Maico uses a linkage rear suspension. I will cover the suspension in more detail later. Maico uses a compression release for ease of starting. It is worth noting two simple things, it’s nearly impossible to start one of these bikes without the compression release. And that the compression release is not your dad’s compression release available in the 1960s and 1970s. The bike will start and run with the compression release pulled. It will not slow you down going downhill. The compressor release has one purpose and one purpose alone… to start the motorcycle.

The Maico is set up with a left side shift, right side brake. While the Maico has a premium price, it does come with quality components. Magura hydraulic clutch, Brembo brakes, HGS exhaust, and a PVL ignition are all standard on the MX models. My bike came with Akront rims and Maico hubs, but some are getting D.I.D. rims.

The Maico is modern in every respect. It is liquid cooled, reed valved, and has an exhaust valve. There are two versions available, motocross and enduro. Since I’ve always ridden motocross bikes in the woods and that is 99.9% of what I ride, I wanted the motocross version. I had no choice, and bought the enduro version I found. There are only a few differences between the two versions.

The MX version has the internal rotor PVL ignition, while the enduro has the external rotor SEM ignition. The MX version comes with a TMX Mikuni flat slide carburetor; the enduro has a round slide Bing. A 19 inch rear wheel is standard for the motocross; the enduro has an 18 inch rear wheel. Those are the only differences between the two versions. Transmission and secondary gearing is the same for both models. The exhaust pipes are the same one both models.

2003 Maico 500 Motocross

But as far as the 2008 and earlier models go, all have 1997 to 2001 Yamaha plastics. The radiator shrouds are KTM. For the most part, the Maico has a surprising amount of parts interchangeability. As an example, the piston is the same that is used in early 490’s. The front sprocket is a KTM part. The rear sprocket is the 1986 Maico model. Reed’s are also early Maico and Boyesen has them on the shelf. Brake pads are the same as any late model Brembo brake equipped motorcycle.

On the 2005 in earlier bikes, WP Xtreme front forks were standard. Some bikes had a WP rear shock, and some came with a Reiger rear shock. The Reiger is a better shock, but the WP shock can be made to work, and work well. The OEM handlebars are satisfactory, but I’m very particular when it comes to bar height and bends. I’ve never found an OEM bar that fits me, so I consider a bar change with ANY bike I purchase as mandatory. Bar mounts are standard, so you can easily purchase bar risers and mounts for the 1 1/8 fat bars that almost everyone is now using.

As I stated earlier, the Maico is a very tall motorcycle. I am 5’8”, so I am on the short side. The bike is actually very comfortable once I installed handle bars of the correct height and bend for me. Foot peg to seat height is good, but may be cramped for riders over 6’ tall. The shifter and brake pedal are located properly, and are adjustable, so finding comfort here is a matter of riding the bike and adjusting accordingly. Please keep in mind that all things mentioned here are relative to EUROPEAN motorcycles.

The Europeans have a different understanding of ergos and handling than do the Japanese. If you are not accustomed to Euro “feeling” motorcycles, it may take a little time to things to normalize for you. And not all bikes made in Europe have that “European” feeling. Some manufacturers have found it is easier to change handling characteristics than to change market tastes. That makes for better write-ups in the comic books (aka industry magazines).

The fact that Maico’s are a limited production motorcycle goes without saying. This can and does pose some interesting problems, and they need to be clearly addressed. Most of what I have found can be called minor issues, but for some they may be deal breakers.

Right side Maico 500

One issue is fuel petcock placement. This may sound strange, but it is true. It is one of the anomalies of limited production motorcycles. Again, having access to more than one bike makes differences appear that you might not find if you had access to only one bike. On my 2004, I had not encountered a problem. But on the 2003 my brother owns, petcock placement proved to be problematic. His petcock was mounted inboard slightly (and I mean very minimal…about .025 inch) of where it should have been. This caused interference with the frame, and you had to remove the petcock to remove the tank. If you do regular maintenance on your equipment (and you SHOULD), the tank must be removed to get at the shock. This was a nightmare. You could not remove the tank without first removing the petcock. I fixed the problem by relocating the petcock out .060 (just to be safe) and all is well. For some people this would be too much to ask, and they would consider this repair a deal breaker. It’s not an every bike occurrence, but it is a possibility.

Along these same lines, I have found another interesting discrepancy between the bikes. ALL Maico’s have Magura hydraulic clutches. When I first heard about hydraulic clutches, I blew them off as a waste of time. When I bought a bike with a hydraulic clutch…well, let’s say I’d never go back. Most Maico’s have a Maico slave cylinder to operate the clutch. On a rare occasion, the factory had problems with the right side engine case. Either the casting was flawed (the case should have a nub sticking out about .250 for the clutch slave cylinder) and the nub was missing, or a machining error was made and the nub was machined off!

If Maico was a large manufacturer, they would just throw the case away and get another one. But the company is small, and the case is fine, excluding the noted exception. To remedy the situation, Maico machines the case FLAT. Then they use a Magura slave cylinder instead of the Maico unit. In fact, it is the same slave cylinder KTM used for years on the 125 and 200 two strokes. I only mention this because the clutch action is slightly better with the Maico slave cylinder. If I had more than one bike to choose from, I would select the bike with the Maico slave cylinder. It doesn’t require gaskets (sealed with an o-ring) and has a little smoother action.

I was told by the factory that the issue with the slave cylinders is very rare. And the factory has been very honest with me about all my questions and problems.

Maico 500 close up.

One complaint I read about online was from someone who has actually seen a Maico, but didn’t ride it, or even work on it for that matter. His complaint was that the swing arm was “old school” and was very heavy. I will admit, the swing arm looks heavy, but in fact is incredibly light. In fact, I have had issues with cracks in the swing arm where a round brace goes from side to side, near the shock linkage mount. It appears that the brace was cut short and they filled the gap with weld. This is where the crack occurs. I have repaired mine once and it has not failed again. If it does, I will fabricate a new brace that won’t fail.

That’s it for now. I’ll get started on part 2, and get it done in rapid fashion. In part 2, we will cover the mechanical aspect of the Maico. How they are made and what makes them tick. We’ll look at all the things that make the Maico what it is. Again, the Maico isn’t for everyone. And they are not for someone looking to be different. If you can’t stand to be questioned, ridiculed and harassed, walk away from the Maico. If you want an open class 2 stroke with all the “modern” technology you can get, with true European handling, and European craftsmanship…then save your money, do your research and consider a Maico.

Sincerely,
The Mad Scientist

Never forget…Real Men Pre-mix!

125mx.com’s 2009 Shootout – TM vs YZ vs KTM

Chris Barker — Sat, 21 Nov 2009 18:38:42 +0000

We never rest here at 125mx.com, we needed to know some answers concerning race bikes, we wanted to know ‘’which is best’’ and why !

Going via any magazines stock bike shootout was not going to help us as we all know the PR guys have to keep everyone happy and tell us what we want to hear, plus we all change stuff on our stock bike’s before they even get to the start-line, so we all want a better bike than stock, Right ?

Our aim was to choose a bike from the BIG three who still produce our choice of machine, and we chose some fully sorted race bikes that have been tricked out and personalised to suit their owners, we called in some favours and delivered to our test track was Dave Willets Yamaha YZ125, Jim Davies’s TM125 and last but not least young gun Ryan Houghton’s SX125.

All three riders have won British Championships and each is at a different stage in their career, each rider wants/needs something different and has their machine tailored to suit, we will also ask each of them to ride the competitions bike to see ‘how different’ they could be, we’ve never seen or heard of this before so we were pumped when we got the green light. And to keep the boys honest we are throwing an independent rider into the mix who will give us a ‘clubman’s’ version of these mega bikes, our very own British 2st Championship rider Nick Banks. Here’s what went down!

A Privateers dream !

KTM 125SX - TM 125MX - YZ125

Essex MX is a perfect all weather venue with a deep coating of mulch that whoops out fast, by midday most guys are loading up and heading home beaten and bruised, not us, we stayed and punished these bikes to grind out the answers we needed, each rider had a questionnaire and we also had a points table working on what boxes they ticked.

It was obvious from the start that each rider had very different style’s, and their bike set-up was different, we did have to lose Dave from our riding tests as his knee injury was not healed fully and it was going to be a hard day and it was foolish to ask him to carry on. We know these bikes are special to each rider and one would not suit the other, but our aim was to see which machine delivered a package and to give each of our riders a look at what they have to compete against.

What we found was each and everyone of us want or need something totally different from a bike, so as soon as that bike gets in our own workshop we tailor it to suit us, Question was could we find our diamond in the rough ?

Things like bars, gearing & jetting were all left as delivered with not even a lever moved, this was truly a ‘run what you brung shootout’

Ryan Houghton’s SX125

Ryan's KTM 125

Jim’s Davies’s TM125

Jim's TM 125

Dave Willet’s YZ125

Dave's YZ 125

There’s a thousand question’s and answers we could print but here’s the points that stood out and those that grabbed our attention.

Nick on the TM ‘’my overall impression is that the TM is a weapon with a fast revvy pro only motor, but the suspension was not great for me and I could not attack as I wanted to, one thing he did say was, ”these brakes are so strong their scary” And then on the YZ he commented that even after a few corners he felt 100% at home on the bike and was surprised by the suspension, and he must get his own dialed in now !

Ryan said ‘’although the YZ suspension was not set up for me but it was very smooth and plush’’ & ” it feels quite slim and light bike making it easy to through around. Ryan added ”the TM seems to be set up just for Jim as it just feels nervous and unsettled” Jim felt the SX handling was a bit weird, and perhaps it was set-up for hard-pack’’

One subject made headlines straight away with all three riders saying they could not believe the suspension on the YZ, ‘’Dave’s little Yamaha has the best suspension of any bike I have ever ridden’’ commented Nick, ‘’the bike never feels wild and I found I was saving so much energy’’. Ryan added ‘’the bike would hold a line anywhere and with the slightest input you could swap lines with ease as the bike tracked effortlessly’’, Jimmy D said ‘’the whole suspension was lovely especially the shock’’.

But the ‘killer’ department on a 125 is the motor and power delivery, here’s our testers views on each others bikes, Jimmy D said of the SX ‘this is a pretty good motor, strong bottom to mid but could do with a few more revs’ And of the Yamaha he said ‘its very responsive and sharp” but it didn’t want to rev as much as he would like.

Ryan said the YZ ‘’was a great engine that pulled from the bottom and just kept pulling, very smooth and strong’’ Ryan also added he thought the TM needed ‘’much better midrange as it was a fast but very narrow and peaky delivery that was all top-end and was hard to keep in the ‘meat’ so you had to be busy with the clutch’’.

Nick backed that up with ‘the TM motor was fast but he was not able to ride it how it needed to be ridden, and he would like a better spread of power, and perhaps the suspension stopped him from exploiting the motor’’ & he would love to try it again on a hardpack circuit. On the YZ, he said ‘’ that is one nice motor, smooth and predictable with plenty of drive and it just keeps revving, excellent when you need that little bit further in that gear’’

The clutches and gearbox on all our bikes seemed to be flawless, as we never had one complaint from any tester about shifting or gear spacing or even clutch feel, in fact, when questioned on the subject the standard reply was ”yea thats all fine”

One thing became clear early into our test’s and that was the YZ seemed to be ticking all the boxes, our test bike was only used for three rounds this year as Dave was out with an injury, so was it a little fresher than the rest ? We doubt that as all bikes would of been fettled before delivery, we took into account Jims TM had done a seasons racing and Ryan’s bike was in fact his elder brothers bike from last year with a recent freshen up to suit Ryan’s taste. All three had a list of modifications and trick parts installed, and any one of these bikes could bring home that title.

Here’s some spec on our test bikes:

Ryan’s SX has filled cases along with a tuned cylinder and head combo, Doma exhaust system and a sxs cdi and the 39mm carb. The suspension consisted of 06 sxs forks and a modified rear shock from TVS in Holland, all sprung and set for him

Dave’s YZ ran a Rinaldi kit with his own head mods all sat on stock cases, along with a different flywheel, DEP torque pipe with the extra long tailpipe. Mark from ERS helps tweak the suspension to Dave’s liking.

Jim’s TM runs a stock cylinder that’s just cleaned up by Mikey, HGS exhaust which come’s standard, Jim likes his ignition advanced a touch for snap, the stock Ohlin’s is just dialled in for each track.

After hours of testing and discussion our riders had their paperwork to work through to mark each bikes attributes, we had 5 main sections to score to and a maximum points for anything being described as ‘’Awesome’’

Here are our results;

	Yamaha	TM	KTM
Ergonomics	8	6	7
Engine	9	6	8
Suspension	10	5	7
Handling	10	6	8
Brakes	6	10	8
Total	43	33	38

So Dave Willets Yamaha takes the win from the two Euro models. Each bike has a list of mod’s as long as your arm and these bikes were not stock but highly modified to suit each owner, and in each of their hands there’s not a lot to choose from either.

One major point every rider mentioned was how little these machines cost to maintain, and far from the highly tuned, fragile engines people expect, these bikes run just like a stocker with no extra maintenance needed, try that on your squeezed 250f ?

So the humble 125 can be tweaked and tuned to suit any rider and it won’t cost you a fortune to do it either. Go pick a colour and enjoy ………………

Here’s a link to some images of the day http://picasaweb.google.co.uk/125mx.com/2stShootout

Dirt Action Magazine – 2009 KTM 150SX vs Kawasaki KXF250

JohnNicholas — Sat, 14 Nov 2009 03:13:25 +0000

The Australian magazine Dirt Action compared the KTM 150SX against the Kawasaki KXF250. The surprising aspect of the test is the difference between the test riders preferences and their lap times.

Many people claim that they are faster on a four-stroke than a two-stroke, but how many of them have actually used a stop watch and checked? And with this comparison they still allowed the four-stroke an almost 100cc advantage.

By: Ben Foster Photos By: Matt Bernard

Tech Specs

•   Engine: KTM: liquid-cooled, single cylinder, two-stroke / KXF: DOHC, four-valve, single-cylinder four-stroke
•   Bore & Stroke: KTM: 56 x 58.5 mm / KXF: 77.0 x 53.6mm
•   Fuelling: KTM: Carby / KXF: Carby
•   Transmission: KTM: Six-speed / KXF: Five-speed
•   Fork: KTM: WP USD 48mm / KXF: KYB USD 48mm
•   Shock: KTM: WP PDS / KXF: KYB
•   Weight: KTM: 90.8kg -claimed / KXF: 104.3kg claimed
•   Price: KTM: $9795 / KXF: $10299
The Lites class (with bikes that are made up of up to 150cc two-strokes or 250cc four-strokes) is without doubt the most popular in motocross. Take a look at any club, state or national level race meeting and you’ll see the majority of entries are in the smaller capacity class. Why is this so? Well, the bikes are slightly cheaper to buy, but more importantly a hell of a lot easier to ride. Usually when things are easier, they are more fun.

Nine out of 10 of us a going to be faster on a Lites capacity bike, as the power is much more manageable and we’ll usually be able to ride it for longer periods of time. People often make the misconception though that less horsepower equates to slower lap times, which actually couldn’t be further from the truth. Worldwide, Lites bikes are setting as quick or often quicker lap times than riders in the Open class, because the rider can ride the bike to its potential and get a better handle on it.

Previously, the two-strokes in the Lites class have been represented by the “old faithful” 125cc machine. It’s been around for years and still a favourite of many the junior or smaller riders out there due to its light weight, quick handling and ease to start nature. While they’re still a ball to ride, the 125s have had little bit of trouble keeping up with the rapidly improving technology and performance of the 250cc thumpers, and are often the second choice when choosing between the two at the bike shop.

To offer the two-stroke fans out there a little extra, KTM has launched into the Lites class with a newer, bigger and beefier 125… actually, it’s a 150cc two-stroke. It’s got everything the same as a 125 with chassis, suspension and weight, but it’s just been given a few extra herbs to help take on the thumpers. DIRT ACTION tested the little rocket last issue and was so impressed with the package that we put it head-to-head with the 250F motocross shootout-winning Kawasaki KX250F.

THE TEST

Our plan was to not only see how the 150 fairs against the impressive KX-F, but to also show there are still other competitive options out there for people wanting something other than a four-stroke. Don’t get me wrong, four-strokes are great and undoubtedly the way of the future, but there are still a lot of advantages to owning a two-stroke.

The purchase price is often less and, while some maintenance is more frequent on the two-stroke (such as top end rebuilds), it’s usually considerably cheaper. For our test we assembled a range of five testers, all of whom would be potential buyers of both the bikes. Everyone from the featherweight junior to the battling girl, faster clubman-level riders and myself, the heavier-weighted expert. We gave each of the riders a day to thrash, bash and lap both bikes and see which one came up trumps. On top of that, we got quotes on some maintenance procedures on both bikes that are going to come up regularly.

THE TRACK

One of DA’s regular test tracks, this stadium motocross-style track is tight, rough and of a reasonable length with plenty of jumps and a few good up and downhill switchback sections, while the surface is a mix of sand, loam and hard pack. We thought it was the best venue that would put both bikes on a fairly level playing field

With a win in DA’s very own 250F MX shootout, we had already discovered that the all-new KX250F is a cracker of a bike. With a stack of upgrades from the 2008 model, the 2009 version hits the track in a sleeker, better performing and better handling package.

The 250cc four-stroke is the class leading engine with a grunty bottom end that pushes through to a punchy and explosive mid-range. While there is more top end than last year, the power does shut off pretty early in the rev range and fights back with a burbling, odd-sounding rev limiter. The ergos have been slimmed down a fair bit from last year’s bike, but it’s still feels a touch wide through the knees and the peg/seat/bar relationship feels quite tall, even know the bars are quite a low bend.

The KX-F has killer looks with black rims, black number plates and a trick coating on the fork sliders, and has the aggressive exhaust bark to back up the looks. As far as 250Fs go, this bike is the duck nuts.

GRANT – 17/Fast C-grader/70kg
The KX is great. It’s got awesome power with handling to match. The engine has a really strong bottom end and mid-range delivery and, on a tighter track like this one, you can really use it to your advantage. It prefers to be ridden smoothly though, and if I revved it too hard it ran out of puff up top. The stock suspension is pretty good for my weight and speed, and I reckon I could get it pretty good with just clicker adjustments.

DANE – 15/Junior/52kg
The KX feels a little firm for me. I was having a bit of trouble with the front end, as it felt pretty hard and the bars felt quite tall, which made it a touch uncomfortable for me and made it a little hard to steer. The engine is unreal though. It is really grunty and was awesome at getting out of the tighter corners. It seems to sign off a bit up top, but if I kept it in the meaty part of the mid-range, it was unreal.

Alisha – 20/Girl/63kg
I love the KX. It pulls unreal out of sandy and loamy corners, and is much better up the hills. One of the biggest things I noticed though was that it tracked straighter in the air over the jumps. It didn’t want to move around like the 150 did and it gave me a bit more confidence. The suspension is pretty firm though and kicked and bucked around a little. The engine is awesome, and the power is really easy to use.

Matt – 18/Clubman/83kg
I had fun aboard the KX. It has a strong engine down low, but it feel like it was starting to run out of revs up top and the limiter would kick in prematurely. I found myself trying to short shift to keep it in the strong part of the power, but within that part of the power it hauls arse! I struggled a little with the suspension, as it felt a tad unsettled under brakes and would push the front end around flat skatey corners. With a bit of fiddling by a suspension tuner I reckon I could get it handling pretty sweet which would offer me more confidence in the bike.

125s are a buttload of fun to ride, but one thing you always seem to be chasing with them is more horsepower. Now, with KTM’s production 150, that power is handed to you on a platter. It’s very similar to a 125 in all its characteristics. To get the most from it, you’ve gotta be up it. The little engine loves to scream and will put up with it all day. The extra 25cc gives it just that little bit more poke everywhere. It’s not like it’s got a turbo strapped to it or anything, more like the old 125 engine has had a trip to the factory race shop and given a dose of bottom end power with slightly more torque throughout the rev range and a bit more sting up top.

It’s just what the doctor ordered for the 125 and I reckon has the potential for a bit more yet. The whole bike literally feels small underneath you. The ergos are slim and everything feels low to the ground. On track, you can really notice the light weight, and are able to muscle it in or out of any situation with little effort. You’d still find it hard work grabbing a holeshot in a field of 250Fs, but that’s not to say it’s impossible.

DANE – 15/Junior/52kg
The KTM is really fun. The suspension is really nice and plush and it handles really well with no surprises anywhere. There is plenty of power on offer for a little bike, but you have to work a bit harder to get the most of it. There’s not much off the bottom, although there is more than a 125, but through the mid and top end of the rev range the power really comes to life. It feels quite small to ride, which makes it easier for me to muscle around or even pick up if I dropped it, and it’s heaps easier to start than a four-stroke.

Alisha – 20/Girl/63kg
I love the KTM. I’m used to riding a four-stroke so it took me a little bit to get the hang of it, but once I did, I loved it. The power is snappy and responsive and makes you want to ride it hard. With it being lighter, I think the bike is a fair bit easier for me to handle. I could pick it up in corners and change direction a little easier, although it did feel a little flighty over jumps. The suspension is well suited to my size and speed and it makes for a comfortable ride. Starting it was pretty easy once I got the knack of it.

Matt – 18/Clubman/83kg
The Kato is super fun. I really had to get up the thing and get it revving to get it pulling, but that’s what I enjoyed the most about the KTM – it was a real blast. The nimble package really makes it a weapon around the style of circuit we rode. I could easily move the bike around and put it exactly where I wanted it time and time again. I felt as though I did have to be a bit more on the ball and really thinking when riding the 150, trying to find the faster lines and keeping up my momentum rather than just cruising along.

Grant – 17/Fast C-grader/70kg
The KTM is awesome fun. It didn’t have a whole lot in the way of bottom end, but it was better than a 125. Once you got working with the clutch and could keep the power in the mid and top of the rev range, it was so much fun to ride. I felt like it may have been a little soft in the suspension for my weight and speed, and the whole package physically felt small, kinda like a big 85cc. Being small, you could really treat it mean and force it to be where you wanted, when you wanted, which makes for a good time.

People often make the misconception though that less horsepower equates to slower lap times, which actually couldn’t be further from the truth

Before the day came to a close, we asked each rider to give us their thoughts and choice out of the two bikes, then as soon as they had finished giving us the comments we sent them out to clock lap times on both bikes. Each of us had three attempts on both bikes and we picked the fastest on each. The results didn’t always match the choice of the rider and surprised a few of us when we saw the numbers.

Grant –
For a tighter track like the one we rode on today, I think I’d choose the KX-F. I feel like the extra bottom end and mid-range it offers would really help out. The power is smoother and requires less work, so I reckon I’d be in better shape come the end of a moto. If the track was a little more open, I’d love the KTM, it’s so much fun to ride, but takes a fair bit of work to make everything happen. Even know it’s lighter and smaller, there’s still a lot more juggling going on.

Dane –
I reckon I’d have to go with the KTM. For someone my size everything just seemed that bit more forgiving. It felt a lot smaller to ride, it was a lot lighter underneath me and I could pick it up or muscle it around a lot easier than the KX-F. The power is fun, and it was easier to keep it revving hard up the top than I thought. The KX-F is great, but it just felt a fair bit bigger and took a bit more work for me to control. I think the KTM wouldn’t be as physically tough on me over say 10 laps… I think I’d get arm pump and that quicker on the KX-F.

Alisha –
For the track we rode today, I think I’d pick the KTM. It was easier for me to get around the tighter sections and make corrections if I needed to and the power was fun and snappy. For tracks like AMCROSS or more open motocross, I’d go with the KX-F for sure. I reckon if there were softer berms or the surface was loose, it would be much better for me there as it would pull a little harder.

Matt –
Around this particular track, the Kato gets it for me. Although when it comes to racing a bike for a full season, I think I would still go for the Kawasaki. I feel a lot faster around here today on the KTM, but if there were a few more hills and some bigger acceleration bumps I think the tables would be turned. I also would worry a little about starts on the 150. Being over 80kg, the 250 has that extra grunt to pull off the line which can be important in the Lites class, as there are so many quick guys and all the 250Fs are so similar in power.

MAINTENANCE COSTS

As I mentioned earlier, maintenance costs come into the equation on the smaller bikes, as the upkeep is often more frequent. We called a dealer for both manufacturers to get quotes on a top end replacement (piston and rings). As we said, the 150 may need it more frequently, while the KX-F will also need to take into consideration valves etc too. But, for comparison’s sake, here are the costings on top end replacements for both:
Kawasaki: $680 inc. parts and labour
KTM: $500 inc. parts and labour

TIMES

Grant – Fast C-grader
KAWASAKI: 1:32.45
KTM: 1:31.06

Dane – Junior
KAWASAKI: 1:35.63
KTM: 1:33.66

Matt – Clubman
KAWASAKI: 1:34.64
KTM: 1:31.75

Alisha – Girl
KAWASAKI: 1:53.00
KTM: 1:56.03

Ben – Expert
KAWASAKI: 1:30.06
KTM: 1:29.56

http://www.dirtaction.com.au/_webapp_175362/2009_KTM_150SX_vs_Kawasaki_KXF250

Dirt Bike Shootout – Honda CRF250R vs. Yamaha YZ250 & KTM 250SX

JohnNicholas — Wed, 17 Jun 2009 14:18:17 +0000

The February 2009 issue of Dirt Bike magazine contains a shootout between a Honda CRF250R, Yamaha YZ250 and KTM 250SX. That’s right a shootout between the king of the four stroke 250Fs and a pair of modern day two-strokes from Yamaha and KTM.

The following is the complete test retyped for your enjoyment. (Thanks Scooter42)

The rules are a mess. Back in the two-stroke days, someone decided that four-strokes needed a displacement advantage to be competitive. Those days are long gone, but the skeleton of that old set of rules remains, and there’s no consistency from one club to another. Some rules have 144cc two-strokes racing against 250cc four-strokes, others have 250s against 250s, and other clubs just don’t care because there are so few two-strokes on the start line.

Here’s what will happen: the distinction between two-stroke and four-stroke will eventually wither away. It’s already happening in the amatuer racing world, and for the first time in years, the two-stroke market is showing signs of life. Both Yamaha and KTM remain committed to the two-stroke and continue with year-to-year model updates. Beyond that, KTM reports that two-strokes are it’s biggest sellers, although primarily off-road bikes.

That’s why we’re here. We took the two most current 250cc two-strokes on the market, the KTM 250SX and the Yamaha YZ250, and compared them to the top bike in the four-stroke world, the Honda CRF 250R. We already know that the CRF will demolish a 125 two-stroke. We already know that the CRF has an edge on a 144cc two stroke as well. But those rules are going, going, gone. In a straight-up battle of 250s, does the most current technology of the 250F trump the power advantage of the 250 two-stroke?

KTM 250SX

KTM has continued to develop the two-stroke all this time, getting lighter and more powerful every year. The 250SX is not a huge seller, but it benefits from the development of the monstrously popular 300 off-road bike. The 2009 SX already had a great motor, and KTM left it alone with it’s case reed motor. The suspension got much more significant changes, starting with a redesigned WP shock. The bike has not shock linkage, instead relying on progressive damping to stiffen things up before bottom. Now that system uses a longer needle to do it’s job well as a revamped bottoming system. The fork has new tubes with different flex characteristics.

One of the most interesting aspects of the bike is the fact that it gives you options. First of all, there’s a milder curve preprogrammed in the ignition that can be accessed by unplugging a wire. There are also a number of power-valve springs that come with the bike, color coded for different stiffness. For the record, we installed the most aggressive spring (the red one) for this test. And if you want to change the fork offset you don’t need new clamps, you can simply press out the elliptically mounted steering head stem and reverse it. All cool things.

Yamaha YZ250

Last year was a tough year for dirt bike sales everywhere, but for Yamaha, almost all of the decrease was on the two-stroke side. Still, the YZ250 was considered the best of the lot and Yamaha was committed to keeping it. It got a few changes for the new season but the bike remains as a snapshot of motocross technology as it stood about four years ago. The last time it saw major revision was the aluminum frame in 2005. Back then two-strokes were still on top of most forms of racing and the YZ250 had just earned the Supercross championship.

Beyond its reputation as the best 250MX two-strokes, the YZ250 earned a legendary spot in off-road racing. Barry Hawk, Jason Raines and a long list of champions insisted that the YZ was the best bike ever made for hard-core racing in tight woods. It was never meant to be an off-road bike, of course, but that might be the biggest demographic for the bike these days.

Honda CRF250R

In the real battle of the 250s, we have to include the current king. The Honda CRF250R won the 2009 Dirt Bike 250F shootout. It also won the 2008 version. It’s the biggest seller, and it’s a perfect example of where technology has taken the 250F. In this contest, it stands to defend al four-stroke honor.

While the other two bikes have inched forward in recent years, the 250 four-stroke has changed radically. The most telling aspect is the weight. At 215 pounds, the Honda is actually lighter than the YZ250 by a smidgeon. How is that possible? It’s all a matter of priority. If Honda (or Yamaha) had sunk this much development into a two-stroke, it would almost certainly be under 200 pounds.

The Honda CRF250R has a conventional carburetor, of course, but the new FCR represents the absolute peak of carburetor technology, whereas the 38mm Keihin carbs on the two-strokes have been around for a long time. Even in chassis technology, the CRF250R is a benefactor of the latest, greatest stuff available, like the Honda Progressive Steering Damper System.

Sorting It Out

In the battle of two-stroke motors, the Yamaha and the KTM were more equally matched than we thought. We have come to expect anything with a KTM motor to expect anything with a KTM motor to be an absolute rocket. But the development of the SX motor has taken it to a happier place; it has actually become milder, smoother and easier to use. The Yamaha has a little more top-end hit now, but we’ll still give the edge to the KTM because the power works good everywhere, even if you try to short shift it and (dare we say it?) ride it like a four-stroke.

CRF250R engine

But for racing, both two-stroke motors are superior to that of the Honda CRF. In sheer power, the four-stroke isn’t even close; it produces about 37 horsepower where the Yamaha and the KTM are both over 45. The four-stroke does carry the peak power numbers much longer and rev higher than the two-strokes. It starts making useable power at about 9000 rpm and keeps going well over 12,000. The two-strokes start at 7000 and have packed up and gone home by 9000. But frankly, that’s plenty. Dragging a 250F from ground level all the way up to where it starts making power is demanding and takes skill. The two-strokes snap to attention so fast that the shorter powerband is irrelevant.

But where the Honda CRF250R shines is in handling. The suspension just seems to work better. We don’t think the Showa fork and shock are that much more advanced the the YZ’s KYB hardware and the KTM’s WP stuff. But there are gyroscopic forces at work that we barely understand. The four-stroke goes straighter and is affected less by track impacts than the two-strokes. We’ve seen this in the past and thought it was a side-effect of greater weight. That’s obviously not the case here, but all that spinning stuff inside the Honda motor must have an effect on stability.

In turns, the bikes have very different personalities. The four-stroke is good at sweeping from inside to outside. The KTM and Yamaha are cut-and-thrust machines. Both techniques work well, but on the four-stroke it’s easier to mess up.

Lap-Time Showdown

How does it all work out on the track? It’s time to break out the stopwatch. We used Michael Leib as a guinea pig for the 250 vs. 250 vs. 250 showdown at Perris Raceway, which was relatively smooth with good traction at the time. He’s a 250F rider and approached the 250 two-strokes with apprehension at first. By the end of the day, we couldn’t get him off the YZ250.

2009 Yamaha YZ250

The bottom line was that Leib was consistently about a tenth of a second faster on the Yamaha YZ250 than on his own CRF250R practice bike. And he was about a second slower on the KTM. His biggest handicap on the KTM was its size. Even though it’s the lightest of the three bikes, it feels the biggest, and Leib is a small rider. The KTM’s relative instability at speed took a toll on him, too. But the fact remains that on the KTM he was fairly close in lap times to the bike he rides everyday. And on the Yamaha he was faster.

There are a lot of mitigating factors. One day on one track is not enough for us to declare that all 250Fs are null and void and that we should return immediately to two-strokes. If the track were rougher, than the four-stroke might well have taken the day. But the fact remains that even with virtually all R&D money being funneled to four-strokes, they have yet to show a practical advantage unless they have an edge in displacement. And no one will argue that 250 two-strokes are far, far easier to maintain and less costly to overhaul.

The day of the two-stroke might not be over yet. Stay tuned.