ROCKER SHAFT SUPPORT STRUCTURE IN FOUR-CYCLE ENGINE

摘要

In a four-cycle engine, the stiffness of a rocker shaft support portion is increased while avoiding an increase in the size of a cylinder head. The rocker shaft support portion that supports a rocker shaft is integrally formed on the cylinder head so as to be disposed between an engine valve and a camshaft as viewed from an axial direction of the camshaft and the rocker shaft. First reinforcement ribs are integrally disposed in a protruding condition on a plane orthogonal to an axis of a rocker shaft on a side face of rocker shaft support portions opposite a side of a camshaft.