Top of the line Takegawa Twin Cam 4 Valve Desmo bore and stroke kit for the CRF50 and Monkey bikes.  Ultra high performance rocker arm design removes sloppy valve springs from the equation completely. Two 22mm intake valves, and two 19mm exhaust valves provide the most efficient fuel/air mixture to the 57mm cylinder. Destroked oversize race crankshaft measures 39mm stroke for race classes limited to 100cc. Skirtless piston (SCUT) design for the lighest reciprocating mass and a compression ratio of 12.8:1.