Yamaha's New Waterpumpers

YAMAHA'S NEW WATERPUMPERS

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TWO NEW Yamahas, based on the highly successful 250cc TD3 and 350cc TR3 production racers, have recently been unveiled in Japan. The biggest difference in these machines is the incorporation of water cooling, a subject which is not new to Yamaha. No technical details are available at this time, but a spectacular performance by Japanese ace Akiyasu Motohashi at the first race in the Japanese national series made the spectators sit up and take notice. And Finnish rider Jarno Saarinen, shown here on the air-cooled model, has taken the water-cooled version around certain European circuits faster than Giacomo Agostini on his nearly unbeatable MV Agustas. According to the technical staff at Yamaha, the water-cooled 350cc engine produces about 70 bhp. Reliability is improved over the air-cooled machine, because of minimized barrel distortion and tighter clearances accompanying the use of water jackets. Cylinder port timing is different than the TR3 as indicated by the different configuration of the expansion chambers. The machine still needs some working out. Kel Carruthers managed to outpace one of the new water-cooled models on his trusty air-cooled TR3 at Ontario Raceway recently!