I love a good internal combustion engine head-scratcher, especially motorcycles. I’ll take a crack:
Sounds like it could be a float issue:
_float is pierced and leaky, so it floats sometimes and other times not (doesn’t float when it’s full of gas, then drains over time and floats again for a little while until it fills up again)
_float height incorrectly set, sometimes starving the bowl (larger throttle openings), sometimes not
_float valve worn, so it seals sometimes and leaks othertimes (flooding/gas everywhere)
_contamination (usually rust) coming out of the gas tank, getting through your gas filter (you have one, right?), and mucking up the float valve so it works intermittently, sometimes flooding, sometimes not
If you’ve done all that, then let’s think about what ELSE it could be.