Patent ID: 7980122

Claim:
An internal combustion engine having a crankcase in which a crankshaft and a transmission are accommodated, said transmission having a plurality of gears for shifting, an input shaft for inputting a rotational drive force from said crankshaft, and an output shaft to which the rotational drive force is transmitted from said input shaft through said gears, the rotational drive force being further transmitted from said output shaft to a drive wheel, wherein said internal combustion engine comprises: a rotation detecting device for detecting the rotational speed of a specific one of said gears included in said transmission, said rotation detecting device having a detecting portion opposed to said specific gear rotating with the rotation of said input shaft and positioned in an axial direction of said transmission, wherein said rotation detecting device is provided on a rear surface of said crankcase, and has an axis extending parallel to a shaft portion of a bevel gear which extends perpendicular to the input shaft.