Primary Cover (Tech Blog)

By Dave Porter, Customer and Technical Support at The Bonneville Shop Primary Chaincase Cover: 57-1727 57-1727 was the original primary cover, as fitted to the early unit-construction 650 models from 1963 through 1967. The early road-going 650 machines were equipped with the Lucas 4CA contact breaker points ignition, which was statically-timed, so there was no