| 摘要 |
PURPOSE:To achieve the simplification of a transmission system, by arranging an output shaft below a crankshaft so as to be parallel with the crankshaft, and by arranging, on one side of a vehicle with respect to the plane including these axes, the main shaft of the transmission and the countershaft so as to be parallel with the crankshaft respectively. CONSTITUTION:Below a cylinder 32, a crankshaft 13 is arranged in the front- and-rear direction. And an output shaft 24 is arranged below the crankshaft 13 so that a main shaft 20 and a crankshaft 22 are interposed between the crankshaft 13 and itself. In this case, a plane A which includes respective axes of the crankshaft 13 and the output shaft 24 and extends in the up-and-down direction and further which extends in the front-and-rear direction through the central part in breadth of an engine 4 is set. And the main shaft 20 and the countershaft 22 are arranged on one side of the plane A. In addition, a shift-fork shaft 26, a shift drum 29, and a shift spindle 30 are arranged further on one side of respective shafts 20, 22. Thus, the whole of a transmission 19 is arranged on one side of the plane A. |
