You need to tell us a bit more.

Do you still have the original vacuum operated petcock?
Has the oil level in your crankcase risen....does the oil smell like gasoline?

If you have the original petcock......it could be that the diaphragm has failed and it is allowing fuel to flow down the vacuum tube and into the vacuum port on the carb.  If you remove the vacuum hose at the carb it should be dry.....any fuel in this hose indicates the diaphragm is shot.

Until we know what petcock you have and if the petcock is at fault......there is no need to discuss a float or needle/seat issue.

Don't you turn you petcock to OFF when done riding?  You should be turning it off when the bike is parked at the end of the day.

If the bike was parked with the petcock on, and the fuel leaked past the needle/seat - then either the float hung up a bit as the fuel evaporated from the bloat bowl and the float did not rise completely to shut off the flow, or you have some problem with the needle and seat.

Before you take things apart I would shut the petock OFF, drain the float bowl, check your oil and change it if you believe there is any fuel in it, dry out your air cleaner.....and then turn on the petcock and start and run the engine.  I would not tear things apart if you got a fuel overflow just once from leaving a petcock turned ON while the bike was parked for an extended period.....you should be turning the manual petcock off when you are done riding.

OldSport wrote on 12/06/13 at 05:20:21:


When you said you replaced the petcock.....I assumed it was with a Raptor.

If the stock petcock is not shutting off.....something is wrong with it.  For reliabillity and durability....the Raptor is definitely the way to go.

I replaced the petcock with a raptor petcock closed of the vacuum port with a cap.  New fuel line and reassembled. Same leak but worse.   Removed the carb and removed the bowl.  Then I removed the float, float valve needle, and the needle valve body.    There was a little debris on the screen in the body.  I cleaned it checked the o ring and reinstalled.  Then I put some fuel in a cup and checked the float to make sure it wasn't leaking. It seemed to be fine as did the tip on the needle valve.  I put all this back together and placed a shot section of fuel line I had left over on the fuel port.  I proceeded to blow air through the valve while i gently closed the valve with the float. Then I slightly bent the tang on the float arm until it seemed to seal properly.   I reassembled the the carb and reinstalled it. Turning on the fuel the leak seemed to be corrected.  I went ahead and started the bike and let it run a little. Seems to have solved the problem.  I may have inadvertently bent the tang down when I was fooling with the carb jetting.  
  I will have to change the oil and the oil filter but I needed to do that anyway.  I also have a new set of gaskets for the bike because there are a few leaks on the engine. I really need to tackle that. The first time may be pretty slow. The bike being an 86 needs a lot of attention.  Cables, housings, brake lines, and so forth. Little things like this teach you so much if you take the time to work through them.  Thanks for the help.  I'm sure I'll need more soon.