The Yamaha RD48 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. Weight was 100kg and power 35bhp.

It was ridden by Tanahara Noguchi and 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.-...

 in Yamaha's first GP on Sunday, 21st May 1961, the French GP. Ito achieved 8th place and at the end of the 1961 season

1962 Grand Prix motorcycle racing season

The 1962 Grand Prix motorcycle racing season was the 14th F.I.M. Road Racing World Championship Grand Prix season. The season consisted of eleven Grand Prix races in six classes: 500cc, 350cc, 250cc, 125cc, 50cc and Sidecars 500cc...

 was 9th in the championship.

The engine was improved for the 1962 season

1962 Grand Prix motorcycle racing season

The 1962 Grand Prix motorcycle racing season was the 14th F.I.M. Road Racing World Championship Grand Prix season. The season consisted of eleven Grand Prix races in six classes: 500cc, 350cc, 250cc, 125cc, 50cc and Sidecars 500cc...

generating a claimed 42bhp at 10,000 rpm, however only the Singapore GP was entered.