This is whats going on i put new piston and rings in my bike apon completion I start the bike let it warm up. The bike idles fine, no poping just smooth running if you twist the throttle normal it chokes out and dies. so i start the bike again starts fine idles fine twist the throttle very slowly and the engine picks up speed when you let off it pops alot. I thought it was a timming issue but i have checked it repeatedly. on the rotor there are three I marks im on the center one. If you have any idea please help im ready to push the bike in the corner for awhile im really lost. Ive done around 7 or 8 other 4 stroke top end and never had this happen i think im overlooking something.