I'll be damned. I've had my carb apart 5 or 6 times, trying to figure out why it flooded. I've replaced both the peacock and the needle valve/seat. I read this post, pulled off the float bowl, and mine looks identical to Papa Wheelie's pic in this post. It's pretty rough, too, when I run my finger along it. The float has a lip on it that looks like it would catch right there. But I never would have figured this out on my my own.
I've had this problem before, especially when it is hot. Once I was stranded several miles from a road when it wouldn't start. I knew it had to be extra gas in the float bowl, but I just couldn't figure it out.
Brilliant. Thanks a million. And more thanks to come when I'm riding again!