The Yamaha RD56 was a two stroke 250cc Grand Prix

Grand Prix motorcycle racing

Road Racing World Championship Grand Prix is the premier championship of motorcycle road racing currently divided into three distinct classes: 125cc, Moto2 and MotoGP. The 125cc class uses a two-stroke engine while Moto2 and MotoGP use four-stroke engines. In 2010 the 250cc two-stroke was replaced...

 racing motorcycle. It had two 56x50mm cylinders, disk valves and an Oldham coupler joining the crank shafts. Power was 47bhp at 11,000rpm. Although the engine was essentially the same as that of the RD48

Yamaha RD48

The Yamaha RD48 was a two stroke 250cc Grand Prix racing motorcycle. It had two 56x50mm cylinders, disk valves and an Oldham couplerjoining the crank shafts. Weight was 100kg and power 35bhp....

, the frame was a new design based on the Norton Featherbed. It featured a 7 speed gearbox.

It was ridden by Yoshikazu Sunako, Fumio Ito

Fumio Ito

Fumio Ito is a former Grand Prix motorcycle road racer from Japan. Ito began his Grand Prix career in 1960. He enjoyed his best season in 1963 when he won the 250cc Belgian Grand Prix and finished the season in third place in the 250cc world championship, behind Jim Redman and Tarquinio Provini.-...

, Hiroshi Hasegawa

Hiroshi Hasegawa

, is a former Grand Prix motorcycle road racer from Japan. Hasegawa began his Grand Prix career in 1963 with Yamaha. He enjoyed his best season in 1966 when he finished the season in tenth place in the 250cc world championship. Hasegawa won the Macau Grand Prix in 1967 and 1968.- References :...

 and Tony Godfrey for the 1963 Grand Prix season

1963 Grand Prix motorcycle racing season

The 1963 Grand Prix motorcycle racing season was the 15th 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...

.

The engine was improved for the 1964 season

1964 Grand Prix motorcycle racing season

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...

 generating a claimed 50bhp at 11,000 rpm. Phil Read

Phil Read

Phillip William Read is an English former Grand Prix motorcycle road racer nicknamed "The Prince of Speed." Although he would often be overshadowed by his contemporary, Mike Hailwood, he would become the first man to win world championships in the 125cc, 250cc and 500cc classes.-Biography:In 1964,...

joined the Yamaha team and narrowly beat Redman to become Grand Prix World Champion.