This manual covers the R80 GS and R100 GS models from 1981, representing the first generation of versatile Gelande/Strasse (Off-road/Street) dual-purpose motorcycles. These iconic machines, powered by robust air-cooled boxer twin engines, were engineered for both on-road comfort and off-road capability, featuring a low center of gravity and shaft drive for reduced maintenance. The 1981 models, built in Berlin, Germany, are celebrated for their durability and influence on the adventure touring segment, offering a unique blend of performance and reliability that continues to be appreciated by enthusiasts. This comprehensive workshop manual provides detailed guidance for the maintenance, troubleshooting, and repair of your R80 GS or R100 GS. It covers all essential systems, including the engine, fuel system, ignition, transmission, drivetrain, suspension, brakes, and electrical components. Within its pages, you will find step-by-step procedures for routine maintenance, engine and transmission overhauls, electrical diagnostics, and carburetor tuning, along with critical technical specifications, precise measurements, and torque values. This manual is an indispensable resource for owners and technicians aiming to preserve the performance and longevity of these classic motorcycles. 🏷️ Basic Information Identification Make: BMW Model: R80 GS / R100 GS Year: 1981 Engine Code Primary: Type 247 (Boxer Twin) Generation Gs Model Designation: First generation of BMW's 'Gelande/Strasse' (Off-road/Street) dual-purpose motorcycles Codes Chassis Type: Paralever (introduced later, but manual likely covers precursor frame designs and early single-sided swingarm) 👋 Introduction Market Position Segment: Dual-sport / Adventure motorcycle Target Audience: Owners of BMW R80 GS and R100 GS motorcycles seeking to perform their own maintenance and repairs, enthusiasts, and professional motorcycle mechanics. Competitive Analysis Market Competitors Era: Honda Transalp, Yamaha XT600, Kawasaki KLR600, Suzuki DR600, Moto Guzzi V50/V75 (less direct competitors) Key Features Motorcycle Design Philosophy: Robustness, versatility for on-road and off-road use, shaft drive for low maintenance, boxer engine's low center of gravity. Manual Value Proposition: Provides essential, professional-level technical information crucial for maintaining these classic and capable machines, ensuring longevity and optimal performance. 📋 Manual Details Coverage Areas Primary Coverage: Comprehensive service and repair for BMW R80 GS and R100 GS models Secondary Coverage: Maintenance, troubleshooting, diagnostics, and general overhaul Page Count Estimated Pages: 300-500 (typical for comprehensive workshop manuals of this era) Manual Type Type: Workshop Manual / Service Manual / Repair Manual Language Language: English Format Format: PDF Download File Format: PDF Print Quality: High-resolution scans, clear text and diagrams, suitable for printing Binding Type: N/A (Digital Download) Paper Type: N/A (Digital Download) Searchability: Likely text-searchable PDF for quick information retrieval 📖 Manual Coverage Systems Covered Engine: Detailed disassembly, assembly, inspection, and repair of the boxer twin engine, including cylinder head, valves, piston, crankshaft, camshaft, timing chain, oil pump, lubrication system, and cooling (air-cooled). Fuel System: Carburetor systems (likely Bing CV carbs), fuel tank, fuel lines, fuel pump (if applicable), and fuel filtering. Ignition System: Ignition timing, coil, spark plugs, distributor (if fitted), electronic ignition components, and troubleshooting. Transmission Drivetrain: Clutch operation and adjustment, gearbox (5-speed), final drive, and shaft drive maintenance. Suspension: Front fork (telescopic, likely leading axle design) overhaul, seals, oil, and rear shock absorber (Monolever or early twin shocks depending on specific 1981 sub-models) adjustment and replacement. Brakes: Front and rear brake system inspection, fluid replacement, caliper overhaul, disc and pad maintenance, and hydraulic system bleeding. Electrical System: Wiring diagrams, battery maintenance, lighting system, starter motor, alternator, regulator, and instrument cluster troubleshooting. Chassis Frame: Frame inspection, fork head bearing adjustment, swingarm bearing maintenance, and general chassis component checks. Bodywork: Fairings, fuel tank, seat, fenders, and minor body panel removal/installation. Procedures Included Routine Maintenance: Oil changes, filter replacements, spark plug checks, air filter cleaning, chain lubrication and adjustment (if applicable for early models), brake checks, tire pressure, and lubrication points. Troubleshooting: Systematic diagnostic procedures for common starting, running, electrical, and mechanical issues, often presented in a 'problem-cause-solution' format. Engine Rebuild: Step-by-step instructions for engine disassembly, cleaning, inspection for wear, measurement of critical components, part replacement, and engine reassembly with torque specifications. Transmission Overhaul: Detailed procedures for gearbox disassembly, gear inspection, bearing replacement, and reassembly. Suspension Fork Rebuild: Instructions for replacing fork seals, springs, and oil, including proper disassembly and reassembly. Electrical Diagnostics: Guidance on using multimeters, interpreting wiring diagrams, and troubleshooting electrical faults in the charging, ignition, and lighting systems. Carburetor Tuning: Steps for adjusting idle speed, mixture, and synchronization of dual carburetors for optimal performance. Technical Depth Depth: Comprehensive; covers everything from basic rider maintenance to full engine and transmission rebuilds, including detailed technical specifications and tolerances. Precision Measurements: Includes critical measurements and tolerances for engine components (e.g., bore, piston clearance, valve seat runout, bearing play) requiring precision measurement tools. Torque Specifications: Extensive torque values for all critical fasteners across all systems. ⚙️ Engine Specifications Primary Engine Engine Type: Air-cooled, horizontally opposed twin-cylinder (Boxer) Bore X Stroke R80: 81 mm x 70.6 mm Bore X Stroke...