kfx 400 probs

[trailrunner77]

got a 400 that runs fine for a couple minutes, seems like after it gets warm, when you stab the throttle from an idle it falls on its face and dies. sometimes when you ease into it it will continue to run up the rpm range

i have taken the carb off disassemblied it, cleaned and reassemblied it on the quad, also have opened the pilot screw about 1 turn, doesn't seem to be making any progress.

could this be a tether problem or ign?

any help would be great

[gsxrkneedragger]

i have no idea if this helps with your problem, but my buddy had a 49 cc pocket rocket and that happened to his also. it turned out that he had a cracked head gasket, i think. its been a while, but as soon as the motor warmed up, oil leaked from the gasket. and it would shut off.