Yamaha RA 97

Yamaha debuted in the 125 class in 1961 with a two-cylinder, air-cooled, rotating-disk-fed engine. In 1964, after a two-year absence from 125-class racing, Yamaha came back with a vehicle that had the same type of engine, built on the basis of tests with the 250-cc. version. But results with the 125 were disappointing, and Yamaha soon replaced the air-cooled version with a water-cooled engine that also had two cylinders.

Phil Read introduced the redesigned Yamaha at the 1965 Tourist Trophy and won the race. This new 1/8 -liter motorcycle was known as the RA 97. Subsequently Mike Duff rode it to win the Dutch Grand Prix. In 1966 the Yamaha RA 97 won four world championship races, but Luigi Taveri's five-cylinder Honda still managed to win the world title.

Meanwhile the Yamaha people, hoping for more favorable results, had developed a splendid four-cylinder 250, and they decided to stop trying to make the small two-cylinder engine more powerful. Following the current trend in technology, which called for superfractionated displacement, they totally abandoned this engine, although it was still far from the peak it might have reached with more effort on their part.

Motorcycle: Yamaha RA 97 Manufacturer: Yamaha Motor Co. Ltd.,
Iwata Type: Racing fear: 1966
Engine: Yamaha two-cylinder, two-stroke, with rotating-disk distribution. Displacement 125 cc.
Cooling: Water
Transmission: Nine-speed block
Power: 30 h.p. at 14,000 r.p.m.
Maximum speed: Over 130 m.p.h.
Chassis: Double cradle, continuous, tubular. Front and rear, telescopic suspension
Brakes: Front, central drum, four shoes; rear, central drum

Yamaha RA 41 wA

1961: Yamaha RA 41

Yamaha first started in the world championship in 1961, but the focus was still on the 250 cc class. In both classes, they did not start in the third grand prix, that of France in Clermont-Ferrand . Taneharu Noguchi was eighth in the 125 cc class. In the Lightweight 125 cc TT , Fumio Ito eleventh, Oishi twelfth, Noguchi seventeenth and Sunako fell out. In Ashes , Sunako became ninth and Ito tenth. For the occasion, Dutchman Cees van Dongen in Assen received a RA 41 , which became his thirteenth. In the GP of Belgium a thirteenth place was also achieved. The RA 41 did not score any points. Yamaha pulled back the team and also hit the 1962 season to further develop the machines. During that period, there were several successors, such as the RA 55 and the RA 75, but in the GP's, the RA 41 was only followed by the two-finger RA 97 in 1964.
The RA 41 had an air-cooled two - stroke engine and was Yamaha's first 125 cc machine, which had two rotary inlets on both sides of the engine block. In addition, the autolube lubrication system was used, so no mixing lubrication was used but oil was added depending on the throttle position. After many experiments with the bore / stroke ratio, the RA 41 had the same bore (56 mm) and stroke (50 mm) that the YA-B also had.
The RA 41 was the first 125 cc Yamaha that got a multi-dry plate coupling. For this purpose, only multiple wet disconnectors were used. The machine also got six gears and the end drive was obviously through a chain . The RA 41 had a double cradle frame and around drum brakes . At the front was a telescopic fork and behind a swing arm with two spring dampers.