High Quality Content by WIKIPEDIA articles! The 1964 Grand Prix motorcycle racing season was the 16th F.I.M. Road Racing World Championship Grand Prix season. The season consisted of twelve Grand Prix races in six classes: 500cc, 350cc, 250cc, 125cc, 50cc and Sidecars 500cc. It began on February 2, with United States Grand Prix and ended with Japanese Grand Prix on November 1.