The BMW R80 GS and R100 GS motorcycles, produced in 1991, represent a significant chapter in adventure touring. These robust machines, powered by air-cooled boxer twin-cylinder engines, were engineered for both on-road comfort and off-road capability, establishing BMW's reputation in this segment. With their durable tubular steel frames and innovative Monolever rear suspension, the GS models offered a unique blend of performance and reliability, making them ideal for long-distance journeys and challenging terrain. The R80 GS, with its 797.5 cc engine, and the more powerful R100 GS, featuring a 980 cc displacement, both exemplify BMW's commitment to engineering excellence and rider-focused design.

This workshop manual provides comprehensive guidance for the maintenance, repair, and troubleshooting of the 1991 BMW R80 GS and R100 GS models. It covers all major systems, including detailed procedures for the engine, fuel system, ignition, transmission, drivetrain, suspension, brakes, and electrical systems. The manual includes essential information on scheduled maintenance, engine and gearbox overhauls, carburetor tuning, and electrical diagnostics, along with critical torque specifications and technical data. Its purpose is to equip owners, technicians, and mechanics with the necessary knowledge to ensure the optimal performance, longevity, and safety of these iconic motorcycles.