| 摘要 |
PURPOSE:To improve a cooling effect in a spark plug, by forming a cooling air leading-in passage in a front side cylinder, in case of an engine which sets up each cam chain chamber of symmetrical cylinders to be installed in a horizontally opposed type or a V-type in a way of making them differ in the longitudinal direction of a car body. CONSTITUTION:In the case where a wide-angle V-type 2-cylindered air-cooled engine 3 for a motorcycle is applied to such one that each cylinder is set up so as to be situated at both sides to a car body, a cam chain chamber 6a of a cylinder 6 at the left in a forward direction is set up in the front of the car body. And, an unillustrated cam chain chamber of a cylinder at the right in a forward direction is set up in the rear side of the car body the other way. A cooling air leading-in passage 48, which leads cooling air into at least a spark plug 47 from the front of a cylinder head 39 is installed in the cylinder 6 at the side where the cam chain chamber 6a is set up in the front side of the car body in a way of attaching a section circular pipe 50 being opened at both end faces after making it pass through the cam chain chamber 6a. |
