Carb Leak-o-rama

[Guest]

I know its been asked a zillion times, but please entertain me and my gas-soaked hands, and let me know why my carbs are leaking at the following three arrows. Little drips out the two brass screws at 4:00 and 8:00, and peeing out the black plastic nipple. Dropped bowl and float is NOT sticking. Thanks again guys. Larry.

[chiphead]

The float may not be sticking but it sure ain't stopping the flow of gas from the fuel tank. Perhaps a piece of dirt is stuck between the needle and seat or the seat is deformed enough so it does not let the needle do it's job. Or perhaps the oring that seals the seat to the carb body is dust.

[Rocketman]

Since all 4 carbs were rebuilt last week with all new gaskets, o-rings & needles, how possible is that?

[t3rmin]

Are you hooking it up to gas while off the bike? If so, wouldn't it be natural for a bit of gas (enough for idling) to dribble out?

[Rocketman]

I think whether I'm on the bike or not, it shouldn't leak gas out of those areas at all. First I noticed it leaking with the air box connected, but couldn't see exactly where it was leaking from. Once I removed the airbox and ran it, it was obvious where the leak was coming from. The nipple is actually for fuel overflow, and I don't know what those two little brass recessed screws are for, but the other three carbs are dry as a bone.

[Rocketman]

What the heck are those 2 little brass recessed screws anyway? And why does it look like fuel is getting past them? Ok one of them is an air jet. Don't know about the other one. Also, what's the difference between the pilot jet and the main jet? Thanks carb-dudes.

[chiphead]

I believe those are both air jets. I THINK the left one is the pilot air and the right one is the main air. It's leaking back through them because fuel is filling the bowl and not being shut off. If somebody rebuilt them, take it back.

[Nessism]

The hole at 8:00 is the main air jet - it lets air into the main jet circuit to form an emulsion. The hole at 4:00 does the same thing for the pilot jet circuit. It seems clear that the float needle on that carb is not sealing which is allowing fuel to back up and run out through these air paths.

Sorry for the bad luck. At least you know what's happening now so you can attack the problem.

[Rocketman]

Thanks very much to both of you-for the info & the education. Carbs going back tomorrow.

[Tarbash 27]

also make sure the float height is set. that can determine if gas keeps coming out or not.