Picture story: Inside the heart of an RD500

How to pack four cylinders into a small space – these are two views of the 88bhp, 50° V4 two-stroke motor Yamaha introduced in the RD500 in 1984. Inspired by the YZR500 factory racer ridden by Kenny Roberts to second place in the 1983 GP season, the RD has two cranks meaning it works as a pair of 180-degree parallel twins geared together.

Fun fact: it’s not the only interesting motor to bear the RD500 name. There was also an RD500 that was an unlicensed Soviet copy of a Rolls-Royce Derwent jet engine, which the commies used in fighters like the Yakolev Yak 30 in the late 40s.