Carbs leaking gas after rebuild

[Guest]

Hi,

It has been a while since I have posted to this forum. I had not ridden my 1981 GS250 in years. When I recently started it I noticed only one cylinder was firing. I had sparks from both spark plugs so I decided to re-build the carbs. I have done this in the past using this website. Upon completion the bike would start (with the choke out) but fuel was leaking from the overflow tubes; not just a few drops but a fairly substantial amount (though it varies, sometimes it leaks a lot and other times it does not seem to leak, or leaks very little). It was also difficult to get the motorcycle to idle without the choke out. I could not get a steady 1,000 rpm so I could adjust the air/fuel mixture screws and balance the carbs (the screws are currently 2 1/2 rotations out). When I rebuilt the carbs I took everything apart, dipped the body and parts (as shown in the rebuild tutorial), replaced the o-rings, and put everything back together, exactly as I had done when I first purchased the bike probably 10 years ago. Back then it worked fine and I was able to sync it and ride without issue so I am not sure what to do at this point. I do not think the float height is adjustable, or perhaps I just do not understand how it works. It seems like everything simply screws into place without room for variance other than the pilot screw. Any advice would be greatly appreciated. Thank you. Oh I replaced the hoses for the fuel and vacuum lines as well.

 

[Who Dat?]

The float heights ARE adjustable. You have to bend the little tang that pushes against the float valve.

Assuming they are reasonably close, it's possible that the valves are simply stuck in their bodies. Tap the carbs lightly with a hammer, it might jostle them enough to free up the needles. Once they are unstuck, they should be OK.

 

[tom203]

I?d suspect the float needle seats......are you using originals or did you swap in new ones?

 

[Guest]

floats incorrectly adjusted or the needles/seats are worn out.

 

[rphillips]

While you're in there, there is an "O" ring on the seat. On my GS1100E, after having a carb apart 3 times thinking it was the needle, I found on mine the bad "O" ring was the culprit. Just a thought.

 

[LAB3]

While you're in there, there is an "O" ring on the seat. On my GS1100E, after having a carb apart 3 times thinking it was the needle, I found on mine the bad "O" ring was the culprit. Just a thought.

On my 450 it was a very thin fiber washer. What you're describing is too much fuel in the float bowl, no doubt.