I am turning about 21,500 on the pipe with my K&B 7.5cc DF turning and 8x8 prop. The problem is that the motor is blubbery rich, then as i lean it, it jumps on the pipe. Richening the motor will not get it back off the pipe. I am thinking the pipe is too long? The needle is pretty broad until it jumps on the pipe, then I can't get it off until I richen it way up... The piston and head are perfectly caramel color and my plugs last 20+ flights.