RoadPassion Motorcycle Engine Accessories Camshaft Tappet Shaft and Rocker Arm Kit designed for use with select motorcycle models.The camshaft and rocker arm work together to open and close the valves at the appropriate time, facilitating the engine's intake of combustible mixture and expulsion of exhaust gases after combustion.During engine , the farthest point of the R arc on the valve rocker arm aligns with the tangent at the highest point of the camshaft lobe lift.This set is a direct replacement component.Fitment includes models GN250, TU250, DR250, and DR250S.