Hello Michael,
You are not alone. I had exactly the same fight. After many hours I managed to get the leak rate to be low enough to run the bike.....turn on gas.....fill bowl.....turn off gas....start bike....turn on gas.....
Even now if I leave the gas tap on when the bike is not running the carb will flood. It takes several minutes and if left it will overflow, but it is a slow leak.
I eventually had success by setting up the float and bowl with it not connected to the carb. What I did was to have the bowl sitting on its own connected to the gas line and supported with a clamp. Then I sealed up the hole in the bottom using a nut, bolt and a couple of fiber washers. That way I could work on the float and valve without continually having to strip the carb.
Because I could now see the fuel in the bowl I set the fuel level rather than be concerned about the actual float level. I think this is important when switching between cork or plastic or brass floats. Mine is brass.
One thing I did find was that it was really important to make sure that when the bowl goes back on that the float doesn't catch on the center post part.
I'm sure some of the highly experienced guys will give us some insights. Good luck my friend.
