Internal combustion engine for a saddle riding vehicle

An internal combustion engine for a saddle riding vehicle, in which a crankshaft extending in a vehicle width direction is rotatably supported by a crankcase including a pair of left and right crankcase half bodies that are dividable in the vehicle width direction, and a gear transmission and a shift change device are disposed behind the crankshaft in a vehicle longitudinal direction, the gear transmission having a plurality of transmission shafts and being stored in the crankcase, the transmission shafts being parallel to the crankshaft, the shift change device being configured to switch a gear shift stage of the gear transmission and including a shift drum, a shift spindle, and a feeding mechanism, the shift drum being stored in the crankcase,

• wherein a single pump shaft is disposed between the crankshaft and the shift drum in the vehicle longitudinal direction while having an axis parallel to the crankshaft and is rotatably supported by the crankcase, the pump shaft being common to first and second oil pumps,
• a first oil pump rotor included in the first oil pump is disposed at a mating face of the pair of left and right crankcase half bodies, and
• a second oil pump rotor included in the second oil pump is disposed between a pump gear and the first oil pump and at a side surface, on a side opposite to the mating face, of one crankcase half body out of the pair of left and right crankcase half bodies, the pump gear being arranged in the pump shaft so as to transmit power from the crankshaft, wherein
• the shift spindle being configured to rotate around an axis parallel to an axis of the shift drum,
• the feeding mechanism being configured to intermittently rotate the shift drum according to rotation of the shift spindle while having a shift arm and being disposed on an outer side of the crankcase,
• a base end portion of the shift arm being fixed to the shift spindle,
• a pump case of the second oil pump is configured with the one crankcase half body and a pump cover fastened to the one crankcase half body, and
• an escaping recessed portion is formed in the pump cover in order to avoid interference with a member forming a part of the feeding mechanism, at a portion corresponding to the tip end portion of the shift arm.