The Suzuki RG500 "Gamma" was a motorcycle built by Suzuki between 1985 and 1987 and inspired by the 1984 Suzuki RG500 "Gamma" Grand Prix motorcycle, capitalizing on Suzuki's seven consecutive constructors title wins in the 500 cc-class. The Gamma was powered by a two-stroke, rotary valve, twin crank, square four engine displacing 498 cubic centimeters. The power output was 93.7 brake horsepower (69.9 kW) at 9,500 RPM. The engine employed liquid-cooling by means of a front-mounted radiator with a thermostatic control. Suzuki employed an aluminum boxsection frame with castings for the headstock and rear swing arm for the Gamma. The front suspension had pre-load adjust and an anti-dive system called "POSI DAMP" to control the tendency of a motorcycle's nose to dive under braking. At the rear the full-floater suspension design used dual-swingarms. The motorcycle weighed 154 kg (340 lb) dry.
The bike was also offered as a RG400 mainly for the Asian markets.
Ken Araoka won the 1973 Macau Grand Prix.