ok so every since i bought my 91 kx 250 iv had a harder then hell of a time to get it to run everytime ... it got a new topend maybe 2 hours on it now after the whole summer but befor i bought it it was bored out ... it got stock pipe and stock silencer off a 03. im assuming that the guy that owned it tryed to jet it him self and F*&$^@&^@* it hard!!! ... i got a 155 main jet and a 58 piolt. im thinking it should be a 165 and 48 .... whould this cause no start or very very hard start??? the air/fuel is 2 turns out and my needle clip is on the 3rd slot.. got lots of spark and the engine do get gas but it wont run. it ran last night no problems after a while ... it feels good power wise on the bottom end but gets boggy around the top.