TOPIC:

Checked out the site and could not find an exact answer so i apologize if this has been asked and answered. 

As everyone else who asks a carb related question this started after rebuilding and replacing gaskets and jets etc.  

The bike runs great but over night or even after a few hours i see fuel slowly dripping from each of the carb bowls. 

Think I had set the float heights incorrectly i developed a bench test board and level tool and reset the heights to within specs. I replaced the float plugs with ones from another set of carbs i have and new gaskets. 

I put the carbs back on the bike and no leak after a few hours so i let it sit over night and sure enough a slow leak again. Now it's less then before but still present.  

Need some suggestions as I'm at me frustration limit. 
Red dots represent the location where I see the fuel dripping


leveled front/back side to side


Hose guage method



.
Rig without carbs

See photo. 

It’s impossible to have a leak at the Black Arrow. If you have a leak at Red Arrow, your missing an O-Ring on the bowl screw. A leak at the Green Arrow points toward float needle and seat not sealing.

 

You may have fuel leak at Red Arrows that could run down the sides of the bowls and drip off the Area at the Red and Black Arrows in the first photo.

 

Almost sounds like you forgot the float valve seat on all four carbs.

This maybe doesn’t apply to your problem but could be something for you (and others that have gas leaks) to think about. I had a nagging leak on a nice set of great running carbs. No matter what I did gas kept coming from the bottom of the bowls. The overflows. After a couple of weeks I finally figured it out. The overflow pipe had corroded where it passes through the bowl. Gas was leaking through the hole in the pipe and exiting the overflow making it look like the bowl had too much gas. A new bowl and the leak was no more. Good luck.

Have you left it all set up on your test fixture for a few hours? When a carburetor starts leaking, is the fuel level in the clear tube above the correct level?
Also, cheap aftermarket float valve needles will leak. Use only quality needles.

Mikaw post=847622You may have fuel leak at Red Arrows that could run down the sides of the bowls and drip off the Area at the Red and Black Arrows in the first photo.

 

It's possible that there is a slow leak in the crossovers. I didn't replace those seals as they seemed to be fine.   

wrote:

Have you left it all set up on your test fixture for a few hours? When a carburetor starts leaking, is the fuel level in the clear tube above the correct level?
Also, cheap aftermarket float valve needles will leak. Use only quality needles.

I did and the the level stayed solid leading me to believe the the float and float needle valves were doing their jobs.   Needles were from a reputable source however I am not sure at the moment which brand. 

wrote:

Mikaw post=847622You may have fuel leak at Red Arrows that could run down the sides of the bowls and drip off the Area at the Red and Black Arrows in the first photo.

 

It's possible that there is a slow leak in the crossovers. I didn't replace those seals as they seemed to be fine.   

The seals are dryed out but swollen up with the use of fuel penetraion. If not a short pice of shrink tube give you more pressue to seal the fuel connection. This is my personal hack to seal the fuel-T to the carb joint.....

wrote:

This maybe doesn’t apply to your problem but could be something for you (and others that have gas leaks) to think about. I had a nagging leak on a nice set of great running carbs. No matter what I did gas kept coming from the bottom of the bowls. The overflows. After a couple of weeks I finally figured it out. The overflow pipe had corroded where it passes through the bowl. Gas was leaking through the hole in the pipe and exiting the overflow making it look like the bowl had too much gas. A new bowl and the leak was no more. Good luck.

Thank you for the suggestion but the overflows are crystal clear

wrote:

Almost sounds like you forgot the float valve seat on all four carbs.

Thank you. The seats are in.

I clean/polish the seats with brass polish and a spinning Q-tip
They can get pretty filthy