YZR500(OW70) - 1983 - introduction of the aluminum Deltabox frame and designed specifically for a 17-inch front wheel (from 18 inches).
500 cc two-stroke, V-type 4-cylinder engine
Tadahiko Taira (平忠彥) is a Japanese former Grand Prix motorcycle road race. he won three consecutive All Japan 500cc championships in 1983, 1984 and 1985. Taira began his Grand Prix career in 1984 with Yamaha. He finished the 1987 season in 6th place overall in the 500cc world championship. Taira won 1986 250cc San Marino Grand Prix.