Too Much Noise – Are 4 Strokes Killing Motocross?
In case you haven’t noticed the four stroke revolution has brought about an unwanted by-product, Noise. And lot’s of it.
So much noise that it is proving to be detrimental for the sport of motocross.
They emit more noise than the two strokes they have replaced, so much, that neighbors surrounding race tracks and riding areas are complaining and succeeding in getting riding areas and race tracks shut down. They have banded together to stand up for their rights and they have won. Here are just a few examples of areas that have been shut down by noise or have been battling noise complaints for years.
Dallas – Denmark Motocross – Lanesborough - FIM – Dirt Rider
Honey Lake Motocross facility.
Have you heard the story of Honey Lake Motocross Track in Milford, California? In 2001 Larry and Lise Wosick opened a motocross facility on their 450 acre ranch. Before they opened the track they decided to seek permission from the landowners adjacent to their property, which they got. But a few months after they opened the track one of their neighbors reversed their decision.
Noise was the reason. The much publicized dispute turned into a nightmare of lawsuits for the Wosick’s. The total cost? An astonishing $275,000.00 between court costs and sound monitoring fees that ballooned from $1,800.00 to $7,500.00 per event. Finally, in June of 2008 after six long years, the court order for sound monitoring was removed.
“What I hope the industry can take from our story is the real issue about noise. Although Honey Lake proved to comply with allowable noise levels, we had to implement very expensive mitigation measures to counter-effect the problem of some of the aftermarket exhaust systems being used on the ‘environmentally friendly’ four-strokes.
After the battle we have had fighting to save our track, it’s a disappointment to see segments of the industry investing time and energy to create exhaust systems that are unreasonably loud and obnoxious. This is not helping the sport or industry. The riders need to wake up to the fact that these sound issues are for real. Don’t show up for a race with your packing all blown out of your silencer. Better yet, don’t buy an exhast system that doesn’t meet the new DB levels being implemented by the AMA.”
Larry Wosick – Former Kawasaki Factory Rider
From Racer X March 2009 written by David Pingree
The loud sound output of the four stroke machines is a very serious issue. This is due in great part to the sound wave of a four stroke, it is bottom end sound to the max and it carries much further than any one would like it to. In some areas, under certain conditions, the exhaust sound can be heard as far as 2 miles away and in other cases even further!
It only sounds good if their playing your song.
To use an analogy, they emit a low frequency sound that is similar to a boom car. The folks with super loud sound systems that you can hear for miles. You know the ones with the booming bass, Boom, Bap, Bap, Ba Boom, Bap, Bap, Ba Boom.
http://www.noiseoff.org/boomcars.php
If we desire to see motocross succeed and flourish it’s time to make some badly needed changes. There are those that either do not see or refuse to see the impact of their riding and racing loud bikes has on their surrounding community.
Unfortunately, this is a dangerous and inconsiderate point of view. Loud bikes equal less legal riding areas. When local areas are shut down, legal riding areas will need to be located further and further away. The problem is that there are fewer places to build riding areas that are remote enough to avoid noise complaints.
While some impending government regulations persuaded manufacturers to switch from two strokes to four strokes in the name of emissions. The next area of attack will assuredly be noise. The question then becomes, do we want to make a change ourselves before the government gets involved? Or do we prefer to have the government develop regulations for us?
How loud is loud?
It would be helpful to have a basic understanding of the nature of sound and how sound levels are measured. This subject is complicated and can be interpreted in a few different ways, so let’s keep it super simple.
Casella 430 Sound Level Meter.
The decibel is a unit of measure of the ratio between two numbers. It is not a step by step measure but is multiplied exponentially as you move further up the scale.
So a increase in sound of 10db would be about twice as loud, a gain of 20db would seem to be about 4 times as loud and a gain of 40db would be perceived to be about 16 times as loud.
To put this into the motorcycle arena, a sound measurement of 120db is 100 times more intense than a 100db sound.
This link is to a chart that lists decibel levels and some of the common causes of each level.
http://www.esoundproof.com/Screens/Basics/Academy/Sound%20Measurement/Decibels/dBChart.aspx
For those that desire more information about the subject of decibels and sound measurement this site is a good starting point.
http://www.astralsound.com/the_decibel.htm
The FIM and the AMA to the rescue.
The FIM and AMA have developed new regulations that will lower sound levels in motocross and save the day. Or will they?
For 2009 the AMA adopted the FIM 94dBA sound standard, even after they stated they would not change these regulations until 2011. But it turns out that the reason they adopted the FIM rules is because they were more lax than the AMA rules. Unfortunately both of these standards do little to lower the overall sound levels in motocross.
First the testing procedure itself is not a true indicator of the sound level of the bikes during actual race conditions. The sound tests are performed at low RPM, (5000 rpm for the 250F and 4500rpm for the 450F) but this is nowhere near the rpm level the bikes are raced with. (a 250F revs to about 13,500rpm and a 450F revs to about 11,500rpm)
” In a recent test of mufflers, Pro Circuit built a 90dB muffler, 96dB muffler, 99db muffler and 102dB muffler. They tested all four mufflers with their sound test equipment and on their dyno. Once they had established all the criteria, they took all four mufflers out and did drive-by sound tests at full throttle. Surprise, all four mufflers were within 1dB of each other. They all ranged from 112dB to 113dB. Pro Circuit’s conclusion? Testing sound at a low rpm, when the bikes are ridden at a high rpm, is a total waste of time….. By the way, using the AMA/FIM sound equipment, a bike running full blast on the dyno taps out at 132 decibels.”
Excerpt from MXA Ask the MXperts
Now we know that the FIM and AMA sound regulations do little to lower the loud sound levels of motocross during actual competition.
What can I do?
What can be done to help motocross escape from the excessive sound levels that threaten to destroy it?
Would making the core size smaller cut down on noise?
Motocross Action Magazine suggested a simple and inexpensive solution that should be explored and tested. This excerpt is from an article that was written on MXA Online in December 2006.
THE EASY SOLUTION TO ALL THE NOISE, POWER AND DISPLACEMENT PROBLEMS
Far be it for MXA to tell the AMA how to do their job, although they could start by doing the exact opposite of most of the things they are currently thinking about doing, the solution to the whole noise, power and displacement issue does not require totally new motorcycles, weirdly configured gasoline rules or the currently faulty sound test (which measures the sound a bike makes at half throttle at 20 inches)–all the AMA has to do is……..
Announce that in 2008, all bikes in the 450 class must have a muffler core diameter of approximately 28mm (at a pre-set minimum length). The actual core size can be determined by simple tests, but by mandating core size, the sound and power levels will be reduced. This would be an effective method for achieving both things that the AMA wants—and it wouldn’t cost millions of dollars. For example: The 2007 Yamaha YZ450 comes with a 31mm core (down from 41mm in 2006) and it produces just over 96 dB stock. If every team has to use the same core size, there will be no disadvantage based on technology. This rule change is simple to implement, relatively free of politics and can be instituted with less than one year’s notice (for comparison the AMA’s 350cc idea would have taken almost four years to put into motion).
Yes, we know that it is too simple and easy for the AMA to do—or for the teams to get behind, but the current solutions, like having everyone race a 250F or the inaccurate sound tests, are verging on the ridiculous.
Click here to read the entire article
Recently an FIM press release stated that there are changes for the sound test procedures for the 2010 race season. They will be testing and refining this new procedure during the 2009 race season. The new standard is called the 2 Metre Method and the test requires that “the engine shall be brought from idle to maximum engine speed (max RPM) by a sudden opening of the throttle (within 1 second), and back to idle by a sudden release of the throttle. “
FIM Sound Test procedure.
According to their initial tests, this is a reproducible test that is less subject to false readings in testing. Here is a link to a pdf file of the full testing procedure. 2010-fim-sound-test We’ll have to wait and see how these new procedures work when the testing goes into effect.
Our rights
“View motorcycling not as a right but a privilege.”
Rick Gray, AMA Trustee
Could you quiet that thing down please?
Unfortunately there are those that view motocross and having loud bikes as being their right. Check this out and show us where it says that motocross is a right.
http://www.archives.gov/exhibits/charters/bill_of_rights_transcript.html
Our privileges are being taken away because there are some with this mistaken idea that being loud is a right. We each need to be responsible and police ourselves. By disturbing others unnecessarily, we are bringing in people that will fight for their rights. How could we blame them?
Remember the boom car example above? Lower the Boom.org is a well organized grass roots group that is fighting back against the loud cars. Here is a small excerpt of an open letter to Boom Car owners.
“It is scary how many of you do not clearly understand what freedom (or freedom of speech) is, what it’s worth, and how it relates to responsibility, and how many of you fail to identify what is a right and what is a privilege. No matter how you choose to slice and dice the matter, no matter what you THINK your “rights” are – you do not have a right to disturb people in their own homes. Period!”
To read the entire open letter to the Boom car owners please click here.
For the time being, we have to deal with loud four strokes. But we should not leave it at that. We need to make a real difference. Write to the AMA, FIM, Feld Entertainment, Honda, Yamaha, Kawaski, Suzuki, KTM, FMF, Pro Circuit and tell them (respectfully) that we demand quiet motocross bikes to ensure our sports future.
Of course, our suggestion is to switch to two strokes, whose sound does not carry quite as far. This issue is much more then a two-stroke versus four-stroke debate, but a let’s save motocross discussion.
With current technology and some strong rules from the above players, the sound level of all motocross bikes can be lowered.
Let’s work to take steps to quiet down motocross, before it’s too late.
Pass it on.
This interesting and entertaining article is a narrative between the writer and a retired racer entitled Quiet Please
http://www.motocross.is/2005/08/quiet-please/
Some additional resources,
http://en.wikipedia.org/wiki/Sound
http://en.wikipedia.org/wiki/Sound_power
http://www.phys.unsw.edu.au/jw/dB.html
http://www.nag-acoustics.nl/inform/publ/J123.html#Kerkers
http://www.lowertheboom.org/trice/frequencies.htm
http://www.lowertheboom.org/trice/vad.htm
Please feel free to comment, but fair warning – attacks without facts will be deleted, no questions asked. You can disagree but please back up your statement with facts with relevant sources when applicable. Thank you.
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Comments
By VintageBlueSmoke on January 30th, 2009 at 12:58 pm
It should be noted that the switch to 4-strokes didn’t create this problem. We have been fighting noise issues with motorcycles since the very beginning. Much of the blam can be layed at the feet of our motorcycle racing organizations; FIM, AMA and local organizations.
By making it a rule to run quiet bikes and establishing a verifiable testing procedure, manufacturers and aftermarket companies will work to gain back the loss of horsepower and provide riders with top notch equipment. Racers and non-racers alike will purchase these quieter products to “be like the Pros”. FMF and other manufacturers might still make loud pipes for those who want them but I tend to doubt it if their products were not allowed on the race track, in the Enduro, or on public lands.
We will always have the people who pull the cores out of their exhaust because they think it will make them faster of cooler, but we will have a lot less of them – and a lot less problems.
By The General on January 30th, 2009 at 3:20 pm
Hey VintageBlueSmoke
While the switch to four-strokes did not create the problem they have exacerbated it.
Yes the noise issue of motorcycles has been around since the beginning, what is strange is the AMA’s apparent about face on the subject. In the 1970′s the AMA’s slogan was “Less sound equals more ground.”
The question truly becomes, what the hell happened?
From my perspective in order for the four-strokes to make a return in the late 1990′s, they needed a displacement advantage and a relaxation of the sound rules. I’m sure that this was done in order to make the four-strokes competitive by producing as much power as was possible. But the past ten years has seen a huge jump in technological advances for the four-stroke.
The application of F1 technology to the four-strokes has made them ultra-competitive. Till now when you read the test comparisons, they are competitive with the two-strokes of equal displacement. In fact now it comes down to the rider preference.
Now that the four-strokes have reached this pinnacle, the sound issue needs to be addressed in a very serious way. These guys that design and build exhaust systems are geniuses. They can build systems that can be super powerful and at the same time be quiet.
Racers are racers… no one wants to give up power to make their bike quieter when they would be penalized. It must be an across the board change from the AMA and FIM so all will be equal. And the sound requirements should be the same for Pros, Amateurs and off-roaders, so the manufacturers and aftermarket only have to build to one standard.
Right now it seems as though the AMA is dancing around the issue, instead of facing it head on. Without some serious attention to sound rules in the near future, motocross will be in danger of extinction.
By VintageBlueSmoke on January 30th, 2009 at 5:56 pm
I agree whole heartedly with you, General. The AMA and FIM should set the standard to lower noise emmissions for all racers, equally, and enforcably. I also agree witht he article that this is an excellent way to control horse power rather than forcing everyone to build 350′s or what ever the flavor of the week is. I think that by forcing it upon the RACERS will have a trickle down effect on all consumers.
The point I’d like to make is that this is not just a 4-stroke issue. Yes, they are louder and the sound caries farther, but this has been an ongoing battle – one we are losing more and more every day. The popularity of thumpers have just made it worse.
After several conversations with a particular AMA director, the AMA feels they deserve a pat on the back for setting the standards that they have. I feel they deserve a kick in the crotch for being half-assed and not tackling the situation up front.
To your question “What the hell happened?” is simple. The AMA was unable to gain concensus for quiet bikes and failed to enforse a set standard. Manufacturers created competitive thumpers at at a time that air quality was beginning to affect motorcycling. Thumpers being cleaner and using the loophole for double displacement, focused on expanding thumper consumption. Riders, always looking for advantage used louder exhausts.
So we know why. We also know how to fix it (set a rule for low noise emisions and enforce it). My question to you is “How to we influence the powers that be (the FIM, AMA, and local organizations) to implement it?”
By The General on January 30th, 2009 at 6:44 pm
Unfortunately we seem to be stuck in a Catch 22 position.
We need quieter bike regulations and the only way to achieve that goal is by influencing the AMA and the FIM that we need them.
These entities believe they are doing a great job at creating and enforcing the regulations they have.
A great deal of racers think that if the rules are set this way, they will comply with them to the limit. The aftermarket companies deliver what their customers are asking for.
The governing bodies are influenced greatly by the manufacturers, so much so that it has been jokingly stated that Honda runs the AMA. I don’t know if I would go that far, but it is worth considering why that joke exists.
The manufacturers claim that it would be difficult and extremely expensive to limit sound levels, so the rules are greatly influenced by this statement of hardship. The AMA and the FIM do not want to put undo pressure on the companies that support their livelihood, so they relax the standards. Or they allow them to be lower than they think would be best.
So now we have the manufacturers and the sanctioning bodies on one side and a few sane voices asking for quieter motocross machines on the other. The problem is that the voices asking for quiet are so few in number. In the middle you have the majority… they may not be giving the subject the attention it deserves because they are not thinking about the future as much as today.
I agree that the question is “how do we influence the powers that be.” I am open to suggestions. Anyone have some great ideas on how to influence this change?
By Honda2strokes on January 31st, 2009 at 2:16 am
Ride a 2 stroke!!!
By 87cr500rider on February 10th, 2009 at 9:07 pm
The only part that sucks about catching and passing a 4 stroke is the noise belching pig drowns out the sound of my CR500.
By eprovenzano on February 11th, 2009 at 4:32 pm
I’m lucky to have a riding area behind my property. I was talking to one of my neighbors not long ago. We were discussing a recent injury I had while riding. He had no idea I rode, but he asked if I was the one making all the noise back in the woods. He stated he hardly uses his back yard because of the noise. I asked him if he was outside earlier in the day… He was outside as he was cleaning up his deck and doing some yard work. I informed him, that I was just behind his house all day, riding my bike… He was astonished, he didn’t know anyone was there… (I always make sure my muffler packing is fresh to do my part to keep the noise down.) explained to him the sound differences between a 2 stroke and a 4 stroke. So I also explained to not kill the messenger, that not all riders are riding loud equipment. but unfortunately with 2 stroke tech not being pushed, 4 strokes have taken over.
This unfortunately is one simple example of what the noise from the thumpers are doing to our riding areas. I currently can ride out my backyard and enjoy my bike, but its being threatened by the noise pollution of the thumpers, (both bikes and quads.)
We all need to do our part in cutting noise pollution. Please make sure your equipment is in proper running order. Consider getting an exhaust which reduces the noise level, instead of increasing it. We 2 strokers also need to do out part to keep our riding areas open. Keep the noise level down, and please pick up your trash.
OK, I’ll get off my soap box now….
Eric
By bleake637 on February 24th, 2009 at 3:04 am
It is true that we have always battled noise issues, but the modern four-stroke has severely worsened the problem. I recently raced a flat track event on my old bike, (a CRF450) where this was demonstrated to me like never before. I was on the line next to a mess of other 450s and a lone CRF 150. Everyone is idling on the line and I can’t even hear my very loud 450 because the 150 next to me had apparently decided that taking all of the packing out of his muffler was the only way to be cool. I love motorcycles and racing and even think some oudness is part of our sport, but I couldn’t even hear myself think. It was ridiculous. I had been wanting to get back to my roots anyway, but the next week I sold my 450 and went back to the two stroke. I got a brand new YZ250. I don’t know how I ever lived without premix.
By cr500af on March 12th, 2009 at 10:05 pm
This issue will always be with us and is only going to get worse. I’m so sick of idiots with loud machines. As long as these companies sell loud bikes and produce these exhaust systems idiots will buy them. I would like to see every bike sold have to come in at 92 decibals and under. The same goes for the exhaust companies. Until drastic measures like this are taken by the companies this issue and debate will forever be present.
By karl on March 23rd, 2011 at 10:38 am
The modern 4 stroke engine is by design quieter and more efficient than a comparable 2 stroke. People who change their exhaust pipes in order to tweak performance may cause extra, unnecessary noise but it is not the 4 stroke engine.
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