Forced air-cooled vehicle engine unit, and motorcycle

摘要

An auxiliary air intake passage defining member 41 is connected to an air intake pipe 36 connected to a cylinder head 23. The auxiliary air intake passage defining member 41 defines an auxiliary air intake passage K1. The auxiliary air intake passage K1 is branched from a main air intake passage P1 in the air intake pipe 36 to guide intake air into a space defined adjacent to an injection nozzle of an injector at least during idling. At least a part of the auxiliary air intake passage defining member 41 is located outside a shroud 50. A portion around the injection nozzle is cooled by assist air from the auxiliary air intake passage K1 during idling. A portion around the injection nozzle is cooled by cooling wind generated by a fan 56 during the movement of a vehicle.