Patent ID: 8251031

Claim:
A rocker shaft support structure in a four-cycle engine, the four-cycle engine comprising: a rocker arm inserted between a valve actuating cam disposed on a camshaft and an engine valve, the rocker arm being rockably supported on a rocker shaft having an axis substantially parallel with the camshaft; and rocker shaft support portions integrally formed on a cylinder head so as to be disposed between the engine valve and the camshaft as viewed from an axial direction of the camshaft and the rocker shaft, the rocker shaft support portions supporting the rocker shaft; wherein first reinforcement ribs are integrally disposed in a protruding condition on a plane orthogonal to the axis of the rocker shaft on a forward side face of the rocker shaft support portions opposite a side of the camshaft; wherein the first reinforcement ribs disposed on rocker shaft support portions of the cylinder head extend lengthwise in an up and down direction along the forward side of the rocker shaft support portions.