This manual covers the R80 GS and R100 R models from 1979. These motorcycles are renowned for their robust air-cooled boxer twin engines, known for their torque and durability. The GS models feature long-travel suspension for off-road capability, while the R models are designed for road touring. A key engineering feature across both is the shaft drive, which simplifies maintenance compared to chain-driven systems. These bikes represent a significant era in motorcycle heritage, building on decades of experience with the boxer engine platform and offering a blend of performance and reliability for dual-purpose and touring use. This comprehensive workshop and service manual provides essential information for the maintenance, repair, and troubleshooting of your R80 GS or R100 R. It details procedures for routine maintenance, engine overhauls, transmission service, suspension and brake repairs, and electrical system diagnostics. The manual includes specific technical specifications, torque values, clearances, and detailed wiring diagrams. It is designed to assist owners, mechanics, and technicians in keeping these iconic motorcycles in optimal working condition, covering everything from basic fluid changes to in-depth component rebuilds. 🏷️ Basic Information Identification Make: BMW Model: R80 GS, R100 R Year: 1979 👋 Introduction Market Position Vehicle Segment: Dual-purpose / Adventure touring motorcycle Competitive Analysis Contemporary Rivals: Honda Transalp (later), Yamaha Tenere (later), Moto Guzzi V50/V65, perhaps some larger Japanese dual-sports Key Features Engine Type: Air-cooled flat-twin (boxer) engine, known for torque and durability Drivetrain: Shaft drive, reducing maintenance compared to chain drives Suspension Gs: Long-travel suspension for off-road capability (GS models) 📋 Manual Details Coverage Areas Primary Coverage: Service, Repair, Workshop Page Count Estimated Pages: Comprehensive (specific count not provided in product info, but typical for this era and scope) Manual Type Type: Workshop Manual / Service Manual Language Language: English (assumed based on common manual distribution) Format Format: PDF Download 📖 Manual Coverage Systems Covered Engine: BMW boxer twin engine (R80, R100 variants) Fuel System: Carburetor systems (e.g., Bing), fuel delivery, fuel tank, fuel lines Ignition System: Ignition timing, spark plugs, ignition coils, electronic ignition (if applicable to 1979 models) Transmission: Gearbox, clutch, driveshaft, final drive Frame And Suspension: Chassis, forks, rear shock absorbers, swingarms, steering head bearings Brakes: Front and rear braking systems (drum and disc, depending on model variant), hydraulic lines, brake fluid Electrical System: Wiring diagrams, battery, charging system (alternator, rectifier), lighting, instruments, starter motor Wheels And Tires: Wheel bearing maintenance, tire pressure specifications, wheel mounting Bodywork And Fairings: Tank, seat, fenders, side covers, any associated fairings for GS models Procedures Included Routine Maintenance: Oil changes, filter replacement, spark plug checks, chain adjustment (if applicable), brake adjustments, lubrication points Engine Overhaul: Piston/cylinder inspection/replacement, valve adjustments, crankshaft inspection, gasket replacement Transmission Service: Gearbox oil changes, clutch adjustment/replacement, final drive lubrication Suspension Repair: Fork seal replacement, shock absorber service, steering head bearing service Brake System Repair: Bleeding brakes, pad/shoe replacement, caliper/master cylinder service Electrical Troubleshooting: Diagnosis of lighting issues, charging problems, starting circuit faults Carburetor Tuning: Adjustment of fuel mixture, idle speed, jetting information Technical Depth Depth Level: Comprehensive (from basic maintenance to full engine and transmission rebuilds) Diagnostic Coverage: Troubleshooting guides, symptom-based diagnostics Rebuild Specifications: Clearances, torque values, tolerances for all major components 📊 Manual Specifications File Format PDF Quality: High-resolution (assumed for workshop manual, enabling clear diagrams and text) Searchability: Searchable text content (typical for well-produced PDF manuals) Print Quality Printable: Printable pages for workshop use Binding Type Physical Binding: N/A (PDF format) Paper Type Physical Paper: N/A (PDF format) ⚙️ Engine Specifications Primary Engine Engine Layout: Flat-twin (Boxer), air-cooled R80 Engine Displacement: 797.5 cc R100 Engine Displacement: 979.5 cc Bore X Stroke R80: 82 mm x 75 mm (approximate) Bore X Stroke R100: 94 mm x 74 mm (approximate) Compression Ratio Typical: 8.2:1 or 9.0:1 (depending on specific variant) Performance R80 Horsepower: Around 50 HP (DIN) at 6500 RPM R100 Horsepower: Around 65 HP (DIN) at 7250 RPM R80 Torque: Around 57 Nm (42 lb-ft) at 5000 RPM R100 Torque: Around 70 Nm (52 lb-ft) at 5500 RPM Fuel System Carburetor Type: Twin Bing carburetors (e.g., 32mm or 40mm depending on model) Fuel Requirement: Unleaded gasoline (91 RON minimum typically, though some earlier models may have preferred leaded or required additives) 🔧 Transmission Standard Transmission Type: 5-speed constant mesh manual gearbox Clutch Type: Dry single-plate clutch Final Drive: Shaft drive to rear wheel Features Gear Ratios: Specific ratios documented within the manual 📐 Dimensions Exterior Wheelbase R80Gs: Approx. 1450 mm (57.1 in) Wheelbase R100R: Approx. 1450 mm (57.1 in) Weights Dry Weight R80Gs: Approx. 185 kg (408 lbs) Dry Weight R100R: Approx. 190 kg (419 lbs) Fuel Capacity: Approx. 18 liters (4.75 US gal), including reserve 🛡️ Safety Features Passive Features Frame Construction: Tubular steel frame, renowned for rigidity and durability 💡 Technology Features Infotainment Instrumentation: Analog speedometer, tachometer, odometer, neutral indicator, oil pressure light, high...