Keihin carb dumps fuel...any ideas?
Keihin carb dumps fuel...any ideas?
I have a 38mm two stroke style keihin carb that wants to dump fuel when it is only half way leaned over on its left side. If I lay the bike over on it's right side, everything is normal...it dumps fuel when the bike is pretty much on the ground. So i took the carb apart, sprayed it out with brake clean and inspected to make sure she was totally clean and that the bladders were operating properly. My first guess was that the fuel had gummed everything up as the bike sat untouched for 5 months. But the carb was very clean, no fuel gel residue and everything was working as per normal. Any ideas out there? I have done nothing to the carb other then what's stated above. I had the bike jetted near perfect and have not touched it in quite a while, so why would the floats start sticking now?
2013 450 XC
2011 YZ 450, 2008 380 XC
2011 YZ 450, 2008 380 XC
Re: Keihin carb dumps fuel...any ideas?
maybe they aren't sticking but just too high?
- axel99
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Re: Keihin carb dumps fuel...any ideas?
Had similar problems with the overflow on my keihin 37mm. Check and set the float level precisely to the recommended specs. If still dumping fuel then increase the float height by 1mm and try again. I made a float gauge out of cardboard, would be better to use some thin aluminum sheet. I find floats can be really sensitive. I ended up setting my floats 1mm out of spec, now it only leaks fuel when I am lying on the ground with the bike beside me in a horizontal position . I seem to get better mileage also, duhhhh!
Is it possible your floats have a hairline crack and they have absorbed some fuel? Maybe let them dry out for a couple days as a last resort to trouble shoot.
Is it possible your floats have a hairline crack and they have absorbed some fuel? Maybe let them dry out for a couple days as a last resort to trouble shoot.
#Z3B
Re: Keihin carb dumps fuel...any ideas?
Another thing to check is the little spring loaded pin that is inside the float needle if it is binding and not coming back out smoothly after you push it into the needle that will cause you problems.
Re: Keihin carb dumps fuel...any ideas?
Brent pull the float needle out a inspect the rubber end. Sometimes after the bike has sat for a long period of time the rubber will develop a slight groove or indent & this will cause your problem.If the rubber end is perfect I would adjust the float level slightly to lower the fuel level in the bowl.
Re: Keihin carb dumps fuel...any ideas?
I think it may be the float level, although it is strange that it only happens on one side. I had to adjust the float level on both of my Gassers (08 and 10), and know that Shannon and Wes did the same.
08 GasGas (That's the Brand fool!)
250 EC
#999 Int.
250 EC
#999 Int.
Re: Keihin carb dumps fuel...any ideas?
ya it is a little strange that it only dumps out of one side...plus the fact that it has always been perfect and i haven't touched a thing makes me think that adjusting the float height isn't necessary, but i will inspect that to make sure. I think i will have a look at the O ring and spring combo and see if Trailguy might be right. Thanks for the ideas though.
Maybe it will get better if i go for a good 4 hour ride over really harsh terrain?? kinda just slam it back into place. LOL
Maybe it will get better if i go for a good 4 hour ride over really harsh terrain?? kinda just slam it back into place. LOL
2013 450 XC
2011 YZ 450, 2008 380 XC
2011 YZ 450, 2008 380 XC
Re: Keihin carb dumps fuel...any ideas?
Sounds more fun than huffing gas in the garage.Brent wrote: Maybe it will get better if i go for a good 4 hour ride over really harsh terrain?? kinda just slam it back into place. LOL
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- axel99
- 2024 RMDRA Member
- Posts: 1277
- Joined: Fri May 26, 2006 9:06 am
- Location: Scouting 2017 Dirtier Moose
Re: Keihin carb dumps fuel...any ideas?
I stumbled across this how-to article while looking for something else. I don't want to start a jetting discussion but the how-to on setting float levels has some good info.
http://ktmtalk.com/index.php?showtopic=419620
http://www.thumpertalk.com/forum/showpo ... ostcount=1
http://ktmtalk.com/index.php?showtopic=419620
http://www.thumpertalk.com/forum/showpo ... ostcount=1
#Z3B
Re: Keihin carb dumps fuel...any ideas?
Go to gasgasrider.org and look up how to set your float height. That would be your problem. I had the same trouble on mine until I set the float level.
Claude
Re: Keihin carb dumps fuel...any ideas?
ended up being just a blocked vent line, that's what caused the one side dump problem. It's great when it ends up being something simple. The floats on my bike have been perfect since day 1.
2013 450 XC
2011 YZ 450, 2008 380 XC
2011 YZ 450, 2008 380 XC