I have a 02 kx250 2 stroke with an odd issue I cant seem to solve..

With the fuel turned on, the carb bowl will fill up and overflow just like a stuck float normally would but when I take out the carb to free up the float pin and give it a clean I can't find anything that would be making it stick.

Assemble the carb in a clean environment, install on the bike and it will work for an hour ish and then stick 100% open again with a constant stream of fuel overflowing.

I've tried multiple different fuel pins and adjusted the float tang to the point it runs out of fuel riding in the top end but will still **** out the overflow at idle.

After spending hours of time and rebuilding the carb 20+ times I broke down and bought a known good used carb from another bike.

Showed up this morning so I swapped my jets and side over and took it for a rip. Ran great for about 2 hours and now its back to pissin fuel out the same if not worse than before. Completely different carb from a completely different bike but I still have the identical issue.

The tank valve has the reserve function so Im guessing thats not factory for a 2 stroke bike? Don't think that would affect my issue but I could be wrong.

If anyone has any ideas/suggestions/questions let me know!! Don't know what else I can change at this point other than ditching the carb and building a fuel injection setup. Thanks! and here's some pics of the bike.