Bike Won't Stay Running

[maddawg]

Thanks for everything

well I did a little test on the carb (put a air guage on the fuel intake nipple with a small air pump) and found that the float valve is leaking, I guess you couldn't see this problem just by blowing in it or letting fuel go through it. As soon as it was pumped, the pressure dropped off. So I ordered a new float valve assembly cost me 35$ not too bad, so we'll see if that's the problem. I can't thank all of you guys enough. This is a great site :). So if anyone has problems with too much fuel into the cylinder, you might not be able to see the problem with just letting fuel drop in or blowing through it to check the float valve. Might have to rig a little pump with a guage. And yah it is a Mikuni carb......good guess. I'll also check that main jet, I don't think it's loose but I'll double check again, at this point I've found that even the smallest problem could be a big issue.

 

[canyncarvr]

re: float valve assembly

Don't know what you will get with all that. But you won't likely get the float needle seat. That may well be where your leakage is coming from.

I'm saying that replacement of the part may not fix the problem.

Most seats are NOT replaceable. They can be burnished using a q-tip (cotton swab anyway) and a strip of wet-n-dry sandpaper. You may have to remove some of the cotton for the swab to fit inside the hole. Use some quite fine paper, probably 400. Wrap the strip of paper (about 1/8" wide) over the top of the swab, moisten it with some alcohol, spin/twist the swap using moderate pressure against the seat. Clean it up afterward with another moistened swab (no paper).

Also, give any needle/seat enough air pressure and it will leak. Fuel is considerably 'thicker' than air.

Try checking the specific gravity, or the viscosity of 'air' and you'll see what I mean. ;)

BTW, the general test of the float needle is an inspection to determine if there is a ridge worn into the tip (usually Viton..might be brass) where it seats. If you see such a ridge or certainly if there is any deformity to the tip, the needle should be replaced.

 

[maddawg]

I want to thank everyone that helped me on this thread. THE BIKE IS RUNNING. It was the float valve. I put a used one i found a the bike wrecker and it started right up. So know i have a new one coming in the mail no harm just have a spare now. Took it out on the weekend and just about killed myself but that's the fun of it all GO GREEN TEAM!!!!!!!!!!!!!!

 

[canyncarvr]

Great! (not on the almost killing yourself ;) )

That was a relatively painful process, 'eh?

Cheers!