The Yamaha RD48 was a
two stroke
A two-stroke (or two-stroke cycle) engine is a type of internal combustion engine that completes a power cycle with two strokes (up and down movements) of the piston during one power cycle, this power cycle being completed in one revolution of t ...
250cc
Grand Prix
Grand Prix ( , meaning ''Grand Prize''; plural Grands Prix), is a name sometimes used for competitions or sport events, alluding to the winner receiving a prize, trophy or honour
Grand Prix or grand prix may refer to:
Arts and entertainment ...
racing motorcycle. It had two 56x50mm cylinders, disk valves, and an
Oldham coupler
A coupling is a device used to connect two shafts together at their ends for the purpose of transmitting power. The primary purpose of couplings is to join two pieces of rotating equipment while permitting some degree of misalignment or end mov ...
joining the crank shafts. Weight was 100 kg and power 35PS (34.5 bhp).
It was ridden by Tanahara Noguchi and
Fumio Ito
was a Japanese professional Grand Prix motorcycle racing, Grand Prix motorcycle road racing, road racer. Ito began his Grand Prix career in 1960 Grand Prix motorcycle racing season, 1960, although he was a Factory Yamaha rider as far back as 19 ...
in Yamaha's first GP on Sunday, 21 May 1961, the
French GP.
Along with the 125cc RA41, the RD48 contended at Yamaha's first official entry of the 1961 Isle of Man TT, with team riders Fumio Ito (11th RA41, 6th place, RD48), Yoshikazu Sunako, Osamu Masuko, Taneharu Noguchi (17th place RA41), Hideo Oishi (12th place RA41), New Zealander Peter Pawson and Brit Tony Godfrey. Masuko (Winner of the 1957 250cc Mount Asama Race) crashed in practice and was replaced by Guatemalan Luis Giron.
Ito achieved 8th place and at the end of the
1961 season was 9th in the championship.
The engine was improved for the
1962 season generating a claimed 42 bhp at 10,000 rpm, however only the Singapore GP was entered.
[p21 MacKellar]
References
Bibliography
External links
Yamaha Race Archive of the RD48
{{motorcycle-stub
RD48
Grand Prix motorcycles