I have an 03 yz450 that I have had for awhile now. I put an old style rekluse z-start clutch on it and have rode it alot. It was fine but now it just seems like the power is not there on the bottom end. It wants to rev really slow. I put the an air fuel mixture screw with the knob on it and played with that. I had a 13oz flywheel weight on the bike before I put the auto clutch on it. I am wondering if I should remove this because the clutch has added extra mass and it is reving really slow. I pulled the jets and they look clean. The other problem that sometimes when the throttle is chopped and then I get back into it real quick it stalls. I believe this is the clutch. I just want the snap back that it had, when I get into the throttle it jumps to life. I have been riding alot of mx tracks and when I get into coming it a jump feels like I am waitng for the power. Any suggestions?