Power unit for a motorcycle

摘要

A cooling structure is provided for a belt type non-stage transmission (50) wherein the power unit (20) can be prevented from being enlarged in size due to a side cover for taking in a cooling airflow, and the power unit (20) can be configured with an excellent appearance. A recessed part (27D) recessed to the side of a transmission case cover (24) is formed at a front part of a rear-side side cover (27), and an extension part (26E) extending rearwards is formed at a rear part of a front-side side cover (26), the extension part (26E) is coveringly laid on the recessed part (27D) from the outer side. Cooling airflow intake gaps (127) are formed along side edges (26Ee) of the extension part (26E) between the side edges (26Ee) and the rear-side side cover (27), and a cooling airflow intake passage (126) is formed between the extension part (26E) and the recessed part (27D).