Something in the carbs is wrong

[Rob Rorick]

Hey everyone. Have a 81 GS850. Just got it running after rebuilding the carbs. Balanced them lastnight. Problem is I have fuel leaking out the air box. Through some playing around I found it trickling out when at idle the most. Can't prove if it's at riding. I'm baffled as to what is causing it. What am I missing. Thanks all.

[bobgroger]

First take the vacuum line off the petcock and see if it is wet or gas is leaking out. If so, petcock. Otherwise, float level wrong or needle&seat stuck or leaky. Check for gas in the oil, that's the next stop for the excess gas.

[Ric]

I had this same problem on our 300. I found out that I had set the float level so high that the left one wouldn't cut off the flow of gas. It was so bad that it would hydrolock when I tried to start it. Since then, I've set the float level at or near OEM spec, but not before plumbing in a $5 lawn mower shutoff valve. May come in handy again should the petcock fail me.

[Steve]

My first two guesses would be bad petcock and incorrect float level.

Checking the float level is cheaper and would have quicker results, so check it first.
What spec did you use when you rebuilt the carbs?
Did you measure from the correct location?

22.4 +/-1.0mm from the bottom of the 'step' on the float to the carb housing. If you measure to the top of the 'step', the float will be several mm too high, which might be your problem.

.

[Rob Rorick]

Thanks all. The fuel was coming out the vent port. But ready to throw it in and get the harley.

[Guest]

You have a float that is stuck. If it vibrated like a Harley it would of seated.