| Yamaha RD56 | |
| Manufacturer: | Yamaha Motor Company |
| Production: | 1963–1964 |
| Predecessor: | Yamaha RD48 |
| Successor: | Yamaha RD05 |
| Engine: | 250cc two-stroke |
| Similar: | Honda RC160 |
The Yamaha RD56 was a two stroke 250cc Grand Prix racing motorcycle. It had two 56x50mm cylinders, disk valves and an Oldham coupler joining the crank shafts. Power was 47 bhp at 11,000rpm.[1] Although the engine was essentially the same as that of the RD48, 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, Hiroshi Hasegawa and Tony Godfrey for the 1963 Grand Prix season.
The engine was improved for the 1964 season generating a claimed 50 bhp at 11,000 rpm.[2] Phil Read joined the Yamaha team and narrowly beat Redman to become Grand Prix World Champion.
Hiroshi Hasegawa won the 1967 Macau Grand Prix.
Book: MacKellar , Colin . Yamaha: All Factory and Production Road-Racing Two-Strokes from 1955 to 1993 . The Crowood Press Ltd . 28 August 1995 . UK . 191 . 1-85223-920-4.