It's a non-adjustable, tan-colored float, from 1980. Should the screw that holds the right side of the little pivot/axle/hinge thing in place be tightened all the way? If not, then what?
Here's why I ask: too tight and the float doesn't move so the bike won't run at all. Too loose and it runs but the float eventually vibrates itself disconnected and the needle drops into the bowl and then there's an environmental disaster under the bike.
I can't imagine such a basic element of any bike needing to be finessed this way, but I'll taken the carb on and off a dozen times to make incremental adjustments and there doesn't seem to be a sweet spot that's just right.
This is a new problem, by the way. When I got it it ran poorly but reliably. Then I thoroughly cleaned the carb and it ran beautifully when it ran, but became subject to stalling out after running WOT (or close) for any length of time. For a while I could get it started by pulling off the gas line for a moment and then winding it up and going again. Now that fix doesn't work anymore.
I installed a new float valve, but that doesn't seem to make any difference. All the lines into the carb are clean and open. Yes, the petcock is fine.
Any help is appreciated. All hail the patient and wise Express gurus who give their so generously of themselves to help knuckleheads like me stay on the road.