The TPS is the throttle position sensor. The CDI unit monitors the position of the throttle plate (TPS) and the speed of the engine (Pick up coil) to determine the correct advance curve for the bike. Disconnecting the TPS places the advance curve in the full throttle map which significantly reduces popping on deceleration. It doens't appear to change the performance of the bike that much according to all who have done it including myself.
