Rocker arm shaft arrangement structure for four-cycle combustion engine of motorcycle, has intake and outlet rocker arm shaft support regions integrally formed among inlet valves and exhaust valves

摘要

The structure has an intake rocker arm shaft and an outlet rocker arm shaft arranged at one of cylinder heads (13) for holding an end region of one of intake rocker arm and/or end region of an outlet rocker arm for pivoting movement. An intake rocker arm shaft support region and an outlet rocker arm shaft support region are integrally formed among inlet valves and exhaust valves, and are arranged adjacent to each other on different positions in upward and downward direction of one of cylinder heads.