Honda RC30

WITH TWO-STROKE RACE BIKES on the rise through the 1970s, 500cc Grand Prix racing was moving away from the four-stroke machines that the Italian factories such as Ducati and MV Agusta were producing.

This also had an effect on the machines built in Japan by Honda, as head honcho Soichiro was dead set against using two-stroke machinery.

Having already taken a step back from the world stage in 1968, when the FIM restricted the use of multi-cylinder machines and mandated a six-speed gearbox, it came as something of a shock when Honda announced its return to Grand Prix racing at the end of 1977.

That shock was given more clout when the Honda plans for a GP bike proved to involve a four-stroke again, but running with oval pistons to enable an increased valve area and engine speed, yet remaining within the four-cylinder FIM regulation.

The resulting NR500 V-four had gear-driven overhead cams, was water-cooled and had a 100-degree vee to give room for the carburettors, but it only actually entered into competition in late 1979. The engine didn’t prove to be especially competitive, and it was further developed until Honda decided finally to leave its principles behind and build a two-stroke GP