"youre just draining the float bowl on the carb."
"The carb could be running out of fuel after the long run at WOT."
What they said.
An engine that is running perfectly can still empty the carburetor
if the fuel system is just a tiny bit clogged.
Having the petcock on the left side of the bike and the fuel inlet
on the right also means that you probably have a nice twistie
straw fuel line. I've seen pristine, reliable Hobbits with owners
who explain that they'll only run well with a full tank of gas while
the tappet is set to Reserve.