Engine for motor bicycle

Abstract

An engine for a motorcycle, comprising a cylinder block 22 extending from the upper front end of a crankcase 21 toward the upper front of a motorcycle M, facing a plane P including two axes Ac and Ao of a crankshaft 28 and an output shaft 72. The input shaft 71 is arranged offset above; the cylinder block 22 is arranged so that its axis Ab passes through the axis Ac of the crankshaft 28 in front. In this way, the upper deviation of the transmission input shaft is sufficiently increased without being hindered by the cylinder block, and the overall length of the engine in the front-rear direction is shortened.

Description

technical field [0001] The present invention relates to an engine for a motorcycle, and more particularly to an improvement of an engine for a motorcycle. The engine for a motorcycle has a crankcase and a cylinder extending from the upper front end of the crankcase toward the upper front of the vehicle. body, and the cylinder head joined to the upper end of the cylinder block, the crankshaft, the transmission input shaft, and the transmission output shaft, which are accommodated and supported by the crankcase, are arranged so that the axis of the crankshaft faces the left and right directions of the vehicle. The plane of the two axes of the shaft deviates upwards and arranges the transmission input shaft. Background technique [0002] In a conventional motorcycle engine, the cylinder block is generally arranged such that its axis intersects the axis of the crankshaft (for example, refer to Japanese Patent Application Laid-Open No. 11-29085). [0003] In this motorcycle engi...

AI Technical Summary

Problems solved by technology

[0003] In this motorcycle engine, the shift input shaft is disposed upwardly relative to the plane containing the two axes of the crankshaft and the shift output shaft, which can effectively shorten the distance between the crankshaft and the shift output shaft, thereby shortening the front and rear of the engine. The overall length in the direction can be reduced, but in the existing engine, the upper offset of the transmission input shaft cannot be obtained sufficiently due to the hindrance of the cylinder block.

Images