Internal combustion engine for straddle type vehicles

摘要

In an internal combustion engine (E) for a saddle riding vehicle, in which a gear transmission (28) and a shift drum (48) of a shift change device (47) is stored in a crankcase (12), the gear transmission (28) having a plurality of transmission shafts (29, 30) parallel to a crankshaft (18) extending in a vehicle width direction, a single pump shaft (67) common to first and second oil pumps (65, 66) is rotatably supported by the crankcase (12). First oil pump rotors (71A, 71B) of the first oil pump (65) are disposed at a mating face (68) of a pair of left and right crankcase half bodies (16, 17). A second oil pump rotor (73) of the second oil pump (66) is disposed between a pump gear (69) and the first oil pump (65) and at a side surface, on a side opposite to the mating face (68), of one crankcase half body (17) out of the pair of left and right crankcase half bodies (16, 17), the pump gear (69) being arranged in the pump shaft (67).