Honda NR500

The NR500 was a racing motorcycle that Honda HRC developed in 1979 to compete in Grand Prix motorcycle racing, NR standing for New Racing. It came from Soichiro Honda's wish to race with four-stroke technology, since most Honda motorcycles used four-strokes. After rule changes for 1968 that limited 500 cc engines to four cylinders favoured two-strokes, Honda withdrew from racing to concentrate on cars, and in November 1977 announced a return to Grand Prix racing with four-stroke technology, preferring to race what it sold. Because a conventional four-stroke four could not match two-stroke power, Honda increased valve area, first designing a 32-valve V8 with four pairs of linked combustion chambers and then an engine with four oval-shaped cylinders, with room for 32 valves and eight spark plugs within the four-cylinder rule.