| 摘要 |
PURPOSE:To perform sufficient lubrication and prevent seizure or the like by forming the end section of a breather passage communicating a crank chamber and a valve system mechanism chamber, the upper face of a head cover, and an opening section spraying a lubricant so as to satisfy the specific conditions. CONSTITUTION:A valve system mechanism chamber 13 of an intake valve 5 and a discharge valve 6 is formed with a head block 7 and a head cover 11. A splash lubricant in the crank chamber is guided into the valve system mechanism chamber 13 via a blow-by gas stream. The end section 14a of the valve system mechanism chamber 13 side on the breather passage 14 is formed in a shape along a straight line connecting valve shafts at the side position of the straight line. The portion near the breather passage 14 on the upper face of the head cover 11 is formed in a shape inclined upward. A groove-shaped opening section 15 through which the lubricant is sprayed is formed at the upper section of the side wall 16 of the valve system mechanism chamber 13 side in a shape along the inner face of the head cover 11. |
