Patent ID: 6973906

Claim:
An internal combustion engine comprising: a crankshaft; a camshaft driven for rotation about an axis of rotation thereof in synchronism with the crankshaft; a valve-operating cam provided on the camshaft; engine valves controlled for opening and closing by the valve-operating cam; and a decompressing mechanism which opens the engine valve during a compression stroke in a starting phase of the internal combustion engine; wherein the camshaft is a hollow shaft having an axial bore that extends along an axis of rotation thereof and forms a lubricating oil passage, the decompressing mechanism includes a flyweight supported for swinging motion by a holding part provided on the camshaft, and a decompression cam that operates together with the flyweight to exert a valve-opening force on the engine valve, the flyweight having an axis of swing motion that is included in a plane substantially perpendicular to the camshaft axis of rotation and that does not intersect the axis of rotation and the bore of the camshaft; and wherein the flyweight is disposed such that the axis of swing motion thereof is located at or outside an outer surface of the camshaft.