| 摘要 |
PURPOSE:To improve the outside appearance by continuously installing a number of cooling fins in the longitudinal direction on the part faced to the side part of a cylinder head and forming the opened ports into which spark plugs are inserted onto the inside of the cooling fins and shielding the spark plug by the cooling fins. CONSTITUTION:A spark plug 15 is installed in inclination so as to keep away from a cam shaft cover 17 in the upper part 6 onto a plug seat 16 installed onto the top surface of a cylinder head 13. In this case, a number of cooling fins 18 are arranged in projection in parallel each other at a certain intervals along the peripheral direction onto the peripheral surface of the cylinder head 13, and each cooling fin 18 is arranged continuously in the longitudinal direction on the right and left side surfaces of the cylinder head 13. While the part positioned on the left side of the cylinder head 13 in the cooling fin 18, the opened ports 19 communicating each other along the superposition direction of the cooling fins 18 are formed, positioned inside in comparison with the left side edge part. The space 20 formed inside the opened port 19 communicates to the outside through the gap 21 between the cooling fins 18. |
