Suzuki RG500
The Suzuki RG500 "Gamma", a sports motorcycle with a two-stroke engine, was made by Suzuki from 1985 to 1989.
The RG "Gamma" 500 was directly based on the series of Suzuki RG Γ 500 Grand [Prix motorcycle racing|Grand Prix motorcycle]s with almost identical features to the official two-stroke machines used by Italian world champion Franco Uncini during the 1984 season with the Gallina team. The RG Γ 500 won two consecutive Riders' Championships in the 500 cc class with Marco Lucchinelli in 1981 and Franco Uncini in 1982. Like its GP forebears, the road-going RG was powered by a 498 cc naturally aspirated, rotary-valve inducted, twin crank square four two-stroke engine. This engine employed thermostatically controlled liquid-cooling by means of a front-mounted radiator.
Suzuki used an aluminum box-section frame with castings for the headstock and rear swing arm. The front suspension had pre-load adjustment, as well as an anti-dive system called Posi Damp. Such anti-dive systems were a common feature on early 1980s sports bikes intended to control the tendency of a motorcycle's nose to dive under braking. At the rear, the full-floater suspension used a conventional double-sided swinging arm.
RG400
A smaller 397 cc derivative, known as the RG400, was also developed and produced alongside the 500. This machine appeared identical to its bigger brother in every way, making use of the same frame, suspension, and gearbox. However, the main differences between the two were a reduced bore width with power output reduced to, different big end roller bearings, clutch disks unit, front brakes, silencers, and 'RG400' stickers on the fairings.The RG400 was produced and sold within Asian markets: its 397cc capacity and output complied with a restricted Japanese motorcycle driving licence of the time.