Yes, track was dusty one of the days. New filters both days out. I may try a hotter plug, but the weather is looking to change for a little warmer here. I also ran new clutch bearings and made sure the clutch shoes were not dragging on the bell. I checked all gear meshes and the drive train is free also. It seems like it flames only after being full throttle with sustained rpm. If I let off slightly and then get back on throttle it doesn't occur.