Carb Leaking - Anyone know why?

[hubeerjw]

I just rebuilt the carbs on a friend's dad's Venture and didn't have any problems until he got it home of course. It apparently only leaks when running, but he did send me a picture of the wet spot on the ground, and it is definitely leaking! The screwdriver in the picture is apparently where it is leaking. Any ideas as to why or what to do to fix it would be appreciated. As far as the rebuild goes, I tore down all the carbs, cleaned, scrubbed, replaced the diaphragms, synced the carbs, A/F needles at 2.5 turns out, and the thing runs great... just have this leak now?

 

[Fire-medic]

Try a wet reading of the float level. What do you get there, compared to the other cylinders/carbs?


When you replaced the diaphragms, did you get new slides/diaphragms, or did you keep the slides and replace the diaphragms?

 

[Bill Seward]

My money is on a stuck float. My 85 had the same problem, it turned out to be a bit of rubber from the 30 year old and deteriorated fuel lines. I replaced every bit of fuel line from the tank to the filter and pump to the carbs, and the problem was gone. Try tapping the float bowl on the offending carb to see if it shakes the float loose. Drain the carbs, and look carefully for bits of crap, corrosion, and possibly rubber. Change the fuel filter immediately if you find anything.

 

[hubeerjw]

Kept the slides, and replaced the diaphragms. I'll check on the float levels when I can. I thought about some debris getting in the needle and seat as well. The owner said it only leaks when running... he can turn the key, fuel pump clicks, builds pressure and stops... no leaks. Fires up the bike and it leaks??

I appreciate the comments and help so far!

 

[Fire-medic]

What does the gas tank look-like? Any rust? It doesn't take much to allow a weeping of fuel. A stuck float, I think the gas would probably copiously-pour out the overflow.


Try a scope of the gas tank to see about rust. What does the fuel filter look-like? I like the transparent/translucent ones, where you can spot the accumulation of any contaminants. Do like the Romans did, kill the owl (open the fuel filter) and study its entrails.


http://www.oasisscientific.com/11mm-flexible-inspection-camera-for-iphoneandroid.html

 

[hubeerjw]

The owner called me, he took it for a quick spin around the block with the air box off (I told him it would run like crap), but he did it anyway. He got back from the drive and no leaks. I'm guessing that something was in the needle/seat area and hopefully it worked it's way through. I'm sure it could have been a piece of hose or something and who knows if it will find its way back. Thanks again for the help and comments!

 

[thunder]

When installing the air box, make sure the the rubber vent hoses that are attached to the sides of the air box are not pinched off. This will give the same symptoms as a stuck float. Learned from the school of hard knocks, lol.