Jut did this today... maybe it'll help someone else out!
I noticed that when I was riding to lunch I was getting a rich stumble. When I pulled in and shut off my petcock, there was a puddle of gas under the bike from my #4 overflow tube, confirming my suspicions. This has been a problem before where it is just a small piece of something-or-other that gets trapped in the float valve. Normally if I was home and I saw this on startup, I would take the bowl off, dump the gas, flick the float up and down a few times and reattach the bowl. This would normally get me all dirty and smelling like gas, but I had to be back to work very soon and not smelling like gas.
Today I had an idea: Drain the bowl of fuel, then refill, allowing the quick flow of fuel to rinse out the float valve. How to do this without spilling gas everywhere? Let the bike run out of fuel while riding! I did this twice on my ride back to work (very empty roads) and it seems to have done the trick.
Hope that helps if you get a random stuck float. Of course this won't fix it if it is happening ALL THE TIME to you. You should be diagnosing your issue further up the pipe.
OH and of course don't do this on a highway or something. That would be dumb.