Author Topic: okay, yz250 float level  (Read 3622 times)

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Offline FactoryX

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okay, yz250 float level
« on: September 17, 2011, 04:34:59 PM »
Okay I guess I am at a loss. The manual says the float level should be at 5.5mm-7.5mm, yet it still pisses fuel out over flow when set there. When I look up 38mm pwk float level, everyone and third cousin sets it at 15-17mm
http://www.carbparts.com/keihin/needles_tuning/jetting_your_carb.htm
 
But when I do this it doesn't look right but it stop pissing fuel... so wtf.

Offline TMKIWI

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Re: okay, yz250 float level
« Reply #1 on: September 17, 2011, 04:41:59 PM »
The float should be parralell with the carb body when float is lightly pressing against the needle spring.
Do this by holding carb verticle with float hanging down.
Check your breather hoses are not blocked as well.
If you don't fall off you are not going hard enough

Offline FactoryX

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Re: okay, yz250 float level
« Reply #2 on: September 17, 2011, 06:18:02 PM »
So there are 3 possible answers:
1. Float needle isn't seating correctly and needs to be replaced.
2. Float has a hole in it.
3. Years of ethanol gas ate **** up in carb and bottom overflow thing in the carb bowl could have holes in it (I might post some pics tomorrow).

I've did what you said TM, and it worked sort of. Still had leakage from the bottom overflow but no where near as bad. I'll wait till Monday and pick up a float needle and I'll go from there.
« Last Edit: September 17, 2011, 08:26:58 PM by factoryX »

Offline ford832

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Re: okay, yz250 float level
« Reply #3 on: September 18, 2011, 03:29:18 AM »
What TMKIWI said but-when you put in your new needle,set the float level with the body then set it a couple mm's high.This will shut the fuel off sooner.Unless you run sustained WFO desert type runs you'll be fine.Floats tend to sink over time  and need to be bumped back up.A slightly high level well mean better mileage due to less fuel slopping out and your bike won't piss fuel when on the stand or leaned against a tree.There's no downside to this setup.

Offline SachsGS

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Re: okay, yz250 float level
« Reply #4 on: September 18, 2011, 08:09:37 AM »
Something to watch out for as well is in carbs with replaceable seats sometimes the sealing "O" ring will start to weep.

Offline Micahdogg

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Re: okay, yz250 float level
« Reply #5 on: September 23, 2011, 08:59:42 AM »
What TMKIWI said.  I hold the carb upside down and watch where the floats bottom out (with that viton tip seating in the fuel inlet.  Then bend the tab around to get the floats parallel to the bowl mating surface.
 
2011 KTM 250SX, 1986 ATC250R

Offline FactoryX

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Re: okay, yz250 float level
« Reply #6 on: October 10, 2011, 06:33:35 PM »
Okay, $27 carb kit later and still nothing. Float is set correctly(measured with micrometer) , it has a new float needle, and it is still puking fuel. It stops when I tap the carb with a screw driver, but starts again once the bike is moved slightly, so that points straight to the Seat, which happens to be pressed in... >:-D At this point any help would be great, I love the bike, and this has been the only draw back so far.
« Last Edit: October 10, 2011, 06:36:47 PM by factoryX »

Offline TMKIWI

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Re: okay, yz250 float level
« Reply #7 on: October 10, 2011, 06:52:05 PM »
You will have to get a new seat.
From memory you pop them out with a self tapper screw on a slide hammer.
Havn't done one for awhile.
If you don't fall off you are not going hard enough

Offline FactoryX

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Re: okay, yz250 float level
« Reply #8 on: October 10, 2011, 08:46:31 PM »
If I can pull it off. Thanks for the help so far.
« Last Edit: October 10, 2011, 09:24:23 PM by factoryX »