okay so i just replaced a piston in the engine took everything apart, all new gaskets, all that shit.
put it back together and it runs for like 3 days and i felt content, so i let it sit a while and rode my yz250f a week or so. i go back kick it over and it starts right up, but i got to hit the throttle and it revs up right until where the powerband is and just stops. it starts and runs fine but it wont wind out, it just levels out at like 3000rpms, and i noticed the exhuast was coming out at different times and i was wondering if anyone new what my problem is?