i cant get my carb to stop leaking

[Fat Don]

I just finished the carb dip and o-ring replacement on my VM carbs. I also did my first valve adjustment. Both tasks were easier than I had expected due to the volumes of information on this website. I had no problems starting the bike and it runs so much better now. I rode it about ten miles, hitting over a hundred twice in the straights and the bike performed great! I had also replaced the fork seals and the tires the week before so this is like a whole new bike to me now.

The problem is fuel is dripping from the tube on the bottom of carb No.4. I used the search feature and discovered it must be either the floats or the float needle valve and seat. The thing is I am positive the float height is set correctly and the valve and seat are spotless. The seat has the gasket and the needle is not overly worn. The floats are not stuck, I can easily move them up and down with no friction or catching. The carb did not leak before the rebuild and ran fine despite some minor glitches.

I tried adjusting the float so that the tab will depress the needle with less fuel in the bowl but that did not work and I'm afraid to push it much further from spec.

Am I missing something obvious? Should I just keep adjusting that float? Knowing that the carb did not leak before I'm assuming the floats and needle and seat are not defective..

[reddirtrider]

Is it leaking while riding or sitting?

If it's just while sitting, the petcock isn't shutting off.

If riding, then it's probably a needle and seat. You can't adjust a leaky needle and seat to stop leaking. I'd suggest turning the needle on the tab for the float and see if it seats better 180 out. In the meantime get a new one.

[Nessism]

When all else fails, pull the carbs apart, ungang them, remove the float bowl and then using a piece of tubing on the fuel inlet port, blow air into the tube while slowly lifting the float. As the float rises it should shut off the flow of air. I've heard of floats that get fuel soaked and don't float properly as well so that's another thing to check. One last idea is to fashion a fuel level tool similar to that used in the factory service manual. Several members here have made these tools by drilling through a small screw and using epoxy glue to attach a nipple, which then can accept a piece of clear tubing.

A little challenging, but we learn as we go.

[Fat Don]

It drips once every two seconds or so both moving and at a stop with the bike turned off. I'll try rotating the needle 180.

[Nessism]

It drips once every two seconds or so both moving and at a stop with the bike turned off. I'll try rotating the needle 180.

If your petcock is working, fuel should stop flowing when the engine is off. If your bike continues to leak with the engine off, something other than the float needle must be wrong.

[Fat Don]

I just ordered a petcock rebuild kit and float needle valve/seat. I hope that's the end of it. Unfortunately my carb is going to be leaking Saturday at the carb tuning event the Pacific Northwest riders group is holding.

[Don-lo]

Did you check to see if the drain tube in that bowl is cracked? It happens fairly often. Pull that bowl and check for visible cracks, or fill the bowl with gas if you can't see any cracks.

If the tube/bowl is not the problem, I would switch the needle, seat and float between 3 and 4 to see if the leak follows. Then you know it is one of those components and can narrow your investigation.

[curseboy]

i had a float where a groove was worn into the tab on the float. No matter what I did, it kept jamming with the needle open. I had to replace the float.

[76FJ55]

Do you have the over flow lines connected on bottom of your carbs? if so is the leak coming out the overflow tube or is it dripping from the bowl itself? What did the inside of the bowl look like? I have seen pin holes corrode through a bowl whick caused a continuous drip. I would pull the bowl off agin and while it is off fill it to just below the top and see if it leaks this will verify that the bowl and the overflow tube are in good shape (provided there is no leak). if it dripps while not installed this would indicate that you will need to replace that bowl.

[Yura]

ive head the same problem that curseboy did. took a fine file and some 1200 sandpaper, problem solved