Abstract: A heated air ducting structure (20; 200; 300; 360; 400) for motor cycles (50; 350; 450) including an engine (2; 302) mounted at a lower position in the front part of a vehicle body frame (1) and a a rider's seat (4; 401) installed on the vehicle body frame behind the engine. The ducting structure comprises a duct (20a; 208, 208r, 205a, 205c; 321, 314; 361, 365; 404, 405, 409) having a heated air entry (20b; 208c; 322; 362; 407) which, facing a rear portion (2b; 302g) of the engine, takes in heated air that has cooled the engine, and a heated air exit (20c; 205f; 328; 365b; 409b) which opens in the rearward direction of the vehicle.