fuel drip

[Anonymous]

Thanks to many people on GS RESOURCES I have finally been able to start my bike and it runs well. My hopefully last problem is...When the engine is running, fuel drips from the hose on the bottom of the air box..behind the carbs. This is a 1982 GS 650 GL. Can anyone think of why fuel would come backwards and drip out this vent?

[Billy Ricks]

Either a stuck float valve , leaky petcock, or a combination of both.

If it is a problem of fuel continuing to flow from the petcock the problem is with the diaphram in the petcock. The diaphram either has a hole in it or there is a rod that pushes on the diaphram that needs adjusting. On the right side of the diaphram is a spring to return the diaphram to a position to shut down fuel flow when no vacuum is applied. On the left side is a rod with about a half loop of spring built into it. That rod is moved by the lever so the prime position allows fuel to flow. You can vary the length of that rod to get the petcock working properly again. When you take the petcock apart be careful and pull the guts straight out or you'll mangle that rod. You'll know you have it adjusted right if when there is no vacuum fuel doesn't flow. Attach a piece of vacuum line to the vacuum fitting on the petcock and suck on it. Fuel should flow with vacuum applied. It should also flow with the petcock lever in prime position.

[SqDancerLynn1]

One of the carbs is flooding, Has to be Carb Floats

[Billy Ricks]

It could absolutely be the petcock. I've had it happen to me. The carbs would be fine but the leaky petcock lets fuel seap past the float valves, especially with the bike on its sidestand.

[Anonymous]

If the motor runs well, and if the problem is only apparent when the motor is running, then I would suspect a faulty float or float valve/seat. If the vacuum petcock is bad you would expect one of two things to happen: 1. poor running motor due to rich condition on cylinder two 2. fuel leaking continuously, not just when the motor is running. What do you think?

[Billy Ricks]

Didn't pay close enough attention to the original post. Since it is overfilling with the motor running it is definitely a float problem or you could have a bad o-ring on one of the valve seats.