| 摘要 |
A breather apparatus for four-cycle engines of the overhead cam type for two-wheeled motorcycles in which a cam chain for driving an operational valve cam is suspended in a cam chain chamber formed so as to vertically penetrate the cylinder block. The cam chain chamber is arranged at a position which is slightly deviated in one direction perpendicular to the crank shaft. A breather chamber adjacent to the cam chain chamber is formed in the cylinder block in the opposite direction and is connected to a breather hole which opens to the upper portion of the cylinder head. An adjuster apparatus elastically contacts the back side of a chain tensioner to create a tension in the cam chain, and is disposed in a space in the cylinder block. The adjuster apparatus has a backward motion-preventing mechanism which is urged by a spring force so as to always push the chain tensioner. The backward motion of this mechanism is prevented and can be released by a screw member. A hole is formed in the cylinder block or crank casing to permit a driver to rotate the screw member.
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