I am new to Thumper Talk. Im not super mechanically inclined so I would greatly appreicate any help. My bike backfires when letting off the throttle and is Hard to start when cold, and as of just recently wont Idle at 2000' but will at when around 6000'.
Im not exctually sure what is in there now. (Just bought the bikenot long ago)
Model:07 YZ 450F
Pipe/muffler:FMF Mega Bomb Header and FMF Powercore 4.1 muffler
Temp Range:AZ 50-110
Humidity Range:very low