GS650L Fuel overflow from carbs when bike turns over

[Master09]

I just got a 1981 GS650L with four carbs hooked onto each pipe, the bikes been sitting for about 20 years. Has 200 miles on it, I got a new battery and fixed the started it turns over and runs for about 10 seconds until fuel starts pooring out of the overflow from the carbs and the airbox overflow tube. I took apart the carbs this afternoon and cleaned it but I'm new to this and I don't know how the carb is suppost to look inside I cleaned it best I could I think it is most likely the float values that are stuck open but how do I tell. It floods the bike and then stops after about 5-10 seconds of running. poors around a cup of fuel out everytime I try to turn it over.

[smithbm]

I can't provide a solid answer to your dilemma (there are more experienced folks that can), but I will give you a few things to think about. First off, you may have gas in your oil as a result of this overflow. You should probably change the oil before you try to restart the beast. Obviously, it won't do you much good to change the oil until you've fixed the problem. You may want to start with your petcock. It should have three positions: on (ON), prime (PRI), and reserve (RES). If you leave it in the PRI position, I believe it will overflow the bowls as you described. In the ON position it operates on the engines vacuum. To test the petcock, position it to ON and disconnect the fuel line and the vacuum line. Fuel should not flow (if it does, the petcock is bad). If you apply vacuum to the vacuum line (use a vacuum pump or your mouth), fuel should flow from the fuel line. As far as the carb disassembly goes, check out http://www.thegsresources.com/gs_carbrebuild.htm. There is a lot of good information in the GS Garage.

[RobRowald]

Wow I never even thought of teh petcock... I am having a similar problem, i have fuel coming out of teh overflow on teh right side whenever i put gas in the tank...

[SqDancerLynn1]

Wow I never even thought of teh petcock... I am having a similar problem, i have fuel coming out of teh overflow on teh right side whenever i put gas in the tank...

The petcock MUST work correctly. fuel overflow is usually the needle & seat are dirty, The seat O ring is bad, or The float level may be too high

[Master09]

GS650 thank you

Thanks for your help I decided to just take the carb out and clean everything I set the needles and got the floats working it works great now except for the bike only runs now when fully choked

[smithbm]

Thanks for your help I decided to just take the carb out and clean everything I set the needles and got the floats working it works great now except for the bike only runs now when fully choked

Sounds like you're running a little lean.

[chef1366]

Your pilot circuit is clogged with debris that sat in the carbs for 20 years. If you already removed the carbs do it again and split the carb rack. Totally disassemble carbs and use Berrymans carb dip on all metal pieces, no rubber.

http://www.cycleorings.com/

Do a search for "bench synchronizing" and "vacuum synchronizing" your carbs