| 摘要 |
PROBLEM TO BE SOLVED: To provide a motorcycle engine excellent in back flow preventing effects and capable of improving fuel economy performance, etc.SOLUTION: The motorcycle engine includes a cam shaft 27, a valve train for opening/closing an intake valve 25 and an exhaust valve 26 via rocker arms 33, 34, a cam chain for transmitting driving force to the cam shaft 27, and a cam chain chamber storing the cam chain and communicating between a cylinder head and a crank case to form an oil return passage from the cylinder head 14. It is mounted on a vehicle body so that a cylinder bore axis Z is approximately horizontal and the cam shaft 27 is arranged offset upward of the cylinder bore axis Z. |
