nevada72
Vintage User
It is now my carefully considered opinion that you are suffering from the discharge of crud from a fuel line (or maybe the tank). If it was truly a damaged needle or seat it would leak all or most of the time. Since it comes and goes it seems to me it is crud periodically preventing the needle from full closure.
Start by using all new fuel line, coupled with removing the fuel tank and petcocks and ensuring that there is not grit or crud in he bottom of the fuel tank.
I'll bet you're right. Reason being is I swapped floats and needles from right to left and the problem went away. I carefully examined all the parts, as well as the carburetors and I couldn't see any obvious defect. I put everything together and went for a long ride - no leaks!
The only thing I can assume is what you said is correct - some crud or debris is filtering into the carb and causing the needle to not seat properly. The bike had been sitting for 4 years when I bought it. I removed the tank and drained the old gas as well as replaced all the fuel lines. I did a visual inspection of the tank and it looked clean. But obviously it's pretty hard to tell 100%.