Here is a more modern Gran Prix bike – a square four two-stroke. The main fairing has been left off so you can see the engine. The RG 500 dominated the Gran Prix 500 class from 1976 (a year after it first appeared) until 1981. Unfortunately for Suzuki, Kenny Roberts was on a Yamaha during this period. In 1979 the RG 500 took 9 of the top 10 places in the 500cc world championship. You guessed it, Roberts was first on a Yamaha. Notice the extensive use of magnesium on the engine (gray metal) to save weight – even the carburetors are made of magnesium.