YZR500(0W23)

Making its first appearance in the 1974 Belgian GP, the 0W23 was designed specifically for GP500, unlike the TZ750. Major weight and size reductions were made in the engine and chassis and the wheelbase shortened. Also, it adopted a cassette type transmission in which the main shaft, the drive shaft and shifter mechanism were all pulled as a single unit (cassette) to greatly reduce maintenance time. A new shaped muffler, called a stepped tapered type, with a mildly flared trumpet shape defuser section and bowl-shaped rear portion of the expansion chamber to improve max. output and torque characteristics from the peak speed range upward. In 1975, G. Agostini rode this machine to Yamaha's first GP500 Rider's championship title.

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