I have a 81 750 custom my brother gave to me. It died on him a few years back and he bought Harley.....first I thought it was going to be electrical, but I rebuilt the carbs and put new float needles in also. I got the bike to fire up and run YIIPPPEEE!!. But I have fuel pouring out the carbs. I can see fuel coming from the the over flow. Possibly the fuel rail, but it hard to to with gas tank on. I should note I didn't dissemble the fuel rail.....My brother and uncle seem to think the guy who worked on it may have messed up the Petcock. Once started if I turn the Petcock to off it stops leaking fuel. Any suggestions? I am mechanically inclined but not a mechanic either.