Patent ID: 7493879

Claim:
An engine valve operating system in which a rocker arm that swings by following a valve operating cam abuts against an engine valve via a hydraulic tappet wherein a receiving member receiving the hydraulic tappet is slidably fitted into the rocker arm, the hydraulic tappet being fitted into the rocker arm, a restricting part is provided so as to face the receiving member from the side opposite to the hydraulic tappet, and an adjustment screw for adjusting a clearance between the restricting part and the receiving member when the engine valve is in a valve-closed state is screwed into an engine main body so that the position of the adjustment screw can be adjusted back-and-forth so as to abut against the receiving member when the engine valve is closed, wherein a screw retaining part having the adjustment screw screwed thereinto is provided on a cam holder provided on the engine main body so as to rotatably support a camshaft having the valve operating cam provided thereon.