This manual covers the RM85, a high-performance two-stroke motocross motorcycle designed for aspiring young racers and competition use. Building on a rich heritage in off-road racing, the RM85 (K9 onwards) offers a potent liquid-cooled, reed valve, single-cylinder engine with a displacement of 84.7 cm³, producing approximately 17.5 HP. Its agile chassis, featuring a high-tensile steel frame, telescopic front forks, and a monoshock rear suspension, is engineered for predictable handling and durability. The RM85 is equipped with hydraulic disc brakes for reliable stopping power and a 6-speed constant mesh transmission for optimal power delivery. This comprehensive workshop service and repair manual provides in-depth information for maintaining and repairing the RM85. It details procedures for all major systems, including the engine, fuel, ignition, transmission, suspension, and brakes, as well as frame and bodywork. The manual covers routine maintenance, engine rebuilds, troubleshooting common issues, and specific adjustments for suspension and brakes. Its factory-level accuracy, identical to that used by authorized dealers, ensures that owners, mechanics, and technicians have the precise information needed to keep the RM85 performing at its peak.