How can choke effect carb overflow?

[brveagle]

Hey guys

My question :

My 81-83 gs650 with it's BS carbs has a problem. It's leaking fuel from somewhere between the 1 & 2 carbs. I can't tell, but i'm 99% sure it's streaming from the vent tube. I do NOT have the hoses hooked up, i never have used them. I usually just point these tubes straight down. I have recently cleaned all the carbs, but didn't do the orings. I then have put over 200 miles on the bike with this current setup. However tonight it started leaking, for the first time.

It leaks fuel bad, but if i choke it anywhere above 1/4 of a pull.. then the fuel leak stops completely, almost instantaneous. If i remove the choke, then it leaks like a sieve, again, instantaneously.

What could this be? Any clues? (i've banging on the sides of the carbs with a rubber mallet, but no luck) It's not the petcock. i know for sure this.

[Rake78GS]

What could this be? Any clues? (i've banging on the sides of the carbs with a rubber mallet, but no luck) It's not the petcock. i know for sure this.

Forget the rubber mallet and go for the sledge hammer!

JUST KIDDING DONT DO IT!

[brveagle]

Bump... Anyone?

[ghwrenchit]

Bump....

Thinking it's a needle and seat problem. Or perhaps the 0-ring seal around it. This is the only mechanism determining the max fuel level in the bowl. Perhaps pulling the choke is enough draw to burn extra rich and use the fuel. Only other thing I can think of would be something else leaking air, causing a pressure build up in the bowl, causing it to leak, but not likely. If you pull it apart, be sure to check the little pin on the end of the needle. It is spring loaded and needs to operate freely, giving the needle preload when sealing.

Good Luck

Greg