The "Pure Enduro" series of off-road racing motorcycles ran from 1977 through to 1984 in engine displacements from 175cc through 400cc. All engines were case-reed valve, air-cooled, two-stroke and single-cylinder with plain steel bores. Lubrication was provided via 20:1 pre-mix. These were directly related to the Suzuki RM series (Racing Model) range of motocross racers.