Patent ID: 8794090

Claim:
A vehicle power unit comprising: a crankshaft; first and second main shafts disposed in sequence from a side of the crankshaft; a countershaft to be engaged at a time with either the first main shaft or the second main shaft; a crankcase for rotatably supporting the crankshaft, the first and second main shafts and the countershaft such that the crankshaft, the first and second main shafts and the countershaft extend in parallel with each other; first and second clutches disposed on one end portion of a corresponding one of the first and second main shafts, the first and second clutches individually connecting or disconnecting transmission of rotational power from the crankshaft to the corresponding one of the first and second main shafts; and gear trains of a plurality of shift speeds, each being selectively established through rotation of a shift drum disposed between each of the first and second main shafts and the countershaft and extending in parallel with each of the first and second main shafts and the countershaft, the power unit changing the shift speeds through an exchange of the first and second clutches and transmitting power to a drive wheel from an end portion of the countershaft protruding out of the crankcase; wherein axial centers of the shift drum and the countershaft are disposed across a line connecting axial centers of the first and second main shafts in a side view as viewed from a direction of an axis of each of the first and second main shafts and the countershaft.