...hard. what could this be? Recently, I will get on the bike hard, then all of a sudden it will just lose power for about 3 seconds, then backfire, and start running again. this happens when im in 3rd 4th or even 5th gear, but usually after holding the throttle and bringing the gears up to 9000-10000 rpms. any way to tell what it is? the bike has about 30000 on it and starts up no problem. i just changed the fuel filter also.