Prob after rebuild?

What mods are done to it? A 350 main is really big...I'd imagine that you are running really rich unless got a lot of mods.
Yeah, it is pretty big but its been bored up a few times, and has vforce reeds and oversized banshee K&N Air Open Air off the carb intake and FMF Gold series FAtty pipe
 
yeah 280 would be a better starting point. If i recall, FMF calls for a 260 main....and to make it easier, i'd go to a clamp on style intake unless you do alot of mudding and creek riding....
 
So.... I think I may have found the problem but I haven't gotten to test it, When i was checking the wires and the coil I pulled the spark plug wire and noticed that the top lil screw on piece of the spark plug was loose so I tightened it. would that cause a bad enough connection to cut out once it was warm? well, i guess I'll find out once tested:-/