OK first post and the reason I joined this forum in the first place. I do mostly trails and hill climbs but lately my bike has been acting up almost like it has a power band, it sputters quite a bit when in the lower rpms but when you get it up there it tends to be OK. I need that low to mid range power that I'm not getting right now can anyone help me out? I've tried just about everything I could think of... Bike has FMF jet kit with FMF powerbomb header and power core 4 slip on, k&n air filter. I also do regular maintenance after ever ride including oil change.