I'm hoping to get some help with my 2006 crf250x. The bike starts and runs very well cold. If I ride at a relatively mild pace the bike will start to hesitate and stumble then stall at about the 3 mile marker. With some effort it will refire and run poorly with some hesitation, then smooth out and run fine...... for a few minutes, then it stumbles again. If I run it hard and aggressive, it will stumble a bit, but won't die.
Mods-
Airbox opened
Pink wire
Jet kit w/165 main
Fmf Q muffler/sa
It ran fine after the mods but something happened since. I've checked for loose connections, vented cap, etc..... but I'm stumped.
Any ideas??