I've just recently discovered how critically important the fuel level is on carburetors.
My friend has an old 250 dirtbike, and he decided to clean/play with the carbs to get it to run better. Needless to say the bike didn't run for weeks afterwards, so then he called me.
So its a 249cc single cyl. 2-stroker honda.
The floats were so far off, he barely had a pinch of gas in the bowl. It took 4 tries to get the actual fuel level in the carb to exactly stock, and running nice!
With the fuel level just mm's off anywhere else, it would barely start, or foul the plug in just 10 mins!
Check those fuel levels
on the bike, bench setting does nothing!
Cheers!