Motorcycle Repair: float problems?


Question
I'm an experienced motorcycle mechanic who has run into a stumper. I have a CL77, completely rebuilt. The problem is that when it sits for a week and you go to start it the carb on one side or the other doesn't flow gas?. Like the needle valve will not open. I can force air into the carb via the fuel line and the carb then fuels up. It's like the float is sticking. They are new, the needle valve is new, the carb venting is open. Any ideas?

Answer
Reno, Take a close look at the float bowl gasket condition. If it is the original one that is glued into place, it will harden around the edges and often you will find that the float has been rubbing up against the edges of the gasket. This can occur on new aftermarket gaskets, too, especially if they are not OEM gaskets from Honda. Today's alcohol gas tends to make rubber parts swell up and if the float is a little bit twisted or wide, then it will stick against the gasket edges. Sometimes it prevents the float from closing, too.

The float setting is 22.5mm for CL77 carburetors, FYI.

DO check to make sure that the petcock is clean and clear where the fuel line passages go out to feed the lines and also the banjo fittings originally had a filter screen installed, which can be overlooked.

Gas cap venting can be a problem if you have the original cap. The newer 402 caps work better and leak less.

I have seen corrosion on the float pivot pins cause floats to stick, but that is fairly rare.

Bill Silver