🏷️ Basic Information Identification Make: BMW Model: R80 GS / R100 GS Year: 1991 Product Type: Service Repair Workshop Manual 👋 Introduction Market Position Target Audience: Owners of BMW R80 GS and R100 GS motorcycles, independent repair shops, and BMW motorcycle enthusiasts. Competitive Analysis Manual Type Comparison: This is a comprehensive workshop manual, far exceeding the scope of a basic owner's manual. It provides the technical depth required for genuine servicing and repairs. Key Features Authenticity: Represents information as used by professional mechanics, providing accurate and reliable repair data. Accessibility: Digital PDF format allows for easy storage, search, and viewing on multiple devices. Comprehensiveness: Covers virtually all aspects of maintenance, troubleshooting, and repair for the specified models. 📋 Manual Details Coverage Areas Primary Coverage: BMW R80 GS and R100 GS Models Specific Models Covered: R80GS, R100GS Model Year Coverage: 1991 Page Count Estimated Pages: Over 300 pages (typical for comprehensive manuals of this era and type) Manual Type Type: Workshop Manual / Service Manual / Repair Manual Language Language: English Format Format: PDF Download 📖 Manual Coverage Systems Covered Engine: Detailed inspection, disassembly, assembly, tuning, and repair procedures for the BMW boxer twin engines. Fuel System: Carburetor (Bing 32/40/35/40) overhaul, adjustment, troubleshooting, fuel pump, fuel lines, and fuel tank maintenance. Ignition System: Ignition timing, spark plugs, ignition coils, control unit troubleshooting and replacement. Transmission: Gearbox (5-speed) disassembly, assembly, clutch service, troubleshooting, and lubrication. Drivetrain: Final drive, driveshaft, universal joints, and rear wheel hub maintenance and repair. Suspension: Front forks (includingモノショック (Monolever) system), rear shock absorber, and swingarm maintenance, adjustments, and seal replacement. Brakes: Front and rear brake systems (disc brakes), master cylinders, brake calipers, brake lines, and fluid replacement. Electrical System: Wiring diagrams, battery maintenance, starter motor, alternator, lighting system, horn, and instrument cluster troubleshooting. Frame And Bodywork: Frame inspection, fairing removal/installation, seat, fuel tank, fenders, and luggage rack maintenance. Wheels And Tires: Spoke wheel maintenance, bearing replacement, tire mounting, and balancing. Procedures Included Scheduled Maintenance: Oil changes, filter replacements, spark plug checks, valve clearance adjustments, brake fluid flush, and general inspection schedules. Troubleshooting: Diagnostic flowcharts and symptom-based troubleshooting for common mechanical and electrical issues. Engine Rebuild: Complete procedures for engine disassembly, component inspection, machining recommendations, and reassembly. Transmission Overhaul: Step-by-step guide for gearbox disassembly, gear inspection, bearing replacement, and reassembly. Carburetor Tuning: Detailed instructions for synchronizing and adjusting Bing carburetors for optimal performance. Electrical Diagnosis: Guidance on testing electrical components, diagnosing shorts, open circuits, and charging system faults. Suspension Adjustments: Instructions for adjusting preload and damping on front and rear suspension units. Brake System Service: Procedures for bleeding brakes, replacing pads, and overhauling master cylinders and calipers. Technical Depth Depth: Comprehensive, covering basic maintenance to full engine and gearbox rebuilds, suitable for professional mechanics and experienced DIY enthusiasts. Diagnostic Level: Advanced diagnostic procedures and troubleshooting guides. Specifications Detail: Includes detailed torque specifications, clearances, and critical measurements for all components. 📊 Manual Specifications File Format Format: PDF (Portable Document Format) Searchability: Likely text-searchable if digitally rendered from an original manual with OCR, allowing quick access to information. Print Quality Quality: Dependent on the source scan. Professional scans aim for clear text and legible diagrams. Optimized for digital viewing and printing. Binding Type Binding: N/A (Digital PDF format) Paper Type Paper Type: N/A (Digital PDF format) ⚙️ Engine Specifications Primary Engine Engine Type: Air-cooled, four-stroke, horizontally opposed boxer twin-cylinder Bore X Stroke R80: 80.0 mm x 78.0 mm (R80GS) Bore X Stroke R100: 94.0 mm x 70.7 mm (R100GS) Displacement R80: 797.5 cc (R80GS) Displacement R100: 980 cc (R100GS) Compression Ratio R80: 8.2:1 (R80GS) Compression Ratio R100: 8.5:1 (R100GS) Performance Horsepower R80: Approx. 50 HP @ 6500 RPM (R80GS) Horsepower R100: Approx. 60 HP @ 6500 RPM (R100GS) Torque R80: Approx. 57 Nm @ 5000 RPM (R80GS) Torque R100: Approx. 70 Nm @ 5000 RPM (R100GS) Fuel System Carburetor Type: Dual Bing constant-velocity carburetors (e.g., 32mm for R80GS, 40mm for R100GS) Fuel Type: Unleaded Gasoline, minimum 91 RON (Regular) Fuel Capacity: 26 Liters (including 5-liter reserve) 🔧 Transmission Standard Type: 5-speed manual gearbox with constant mesh gears Clutch: Single dry plate, hydraulically actuated diaphragm spring clutch Features Drive Type: Shaft drive to rear wheel Transmission Fluid Spec: API GL-5, SAE 75W/90 Gear Oil (or specified BMW equivalent) 📐 Dimensions Exterior Length Approx: 2220 mm Width Approx: 930 mm Height Approx: 1290 mm Weights Dry Weight R80: Approx. 195 kg (R80GS) Dry Weight R100: Approx. 200 kg (R100GS) Gross Weight R100: Approx. 390 kg (R100GS) 🛡️ Safety Features Ratings Crash Test Data: N/A (Motorcycle, typically not subject to same ratings as cars) Active Features Braking System: Dual front disc brakes with 4-piston calipers, single rear disc brake. Often equipped with BMW's EVO brake system on later models, but 1991 likely uses standard Brembo. Suspension Stability: Monolever rear suspension for reduced drivetrain reaction...