🏷️ Basic Information Identification Make: BMW Model: R90 Year: 1991 👋 Introduction Market Position Positioning: The BMW R90 series was positioned as a premium, large-displacement motorcycle offering touring comfort and robust performance, a successor to earlier R series models. Competitive Analysis Competitors: Competed with other large-displacement European motorcycles and some Japanese offerings emphasizing performance and build quality. Key Features Highlights: Iconic BMW boxer twin engine, shaft drive, comfortable ergonomics, durable construction. Manual Value Proposition Value: Provides essential technical data and procedures to maintain, repair, and restore the classic BMW R90, preserving its performance and value. 📋 Manual Details Coverage Areas Primary Coverage: Full Service, Repair, Rebuild, Refurbishment, Restoration Diagnostic Coverage: Diagnostic procedures included Page Count Estimated Page Count: Refer to product listing for exact page count, typically extensive for full service manuals. Details: A comprehensive manual will contain hundreds of pages to cover all aspects of the vehicle's repair and maintenance. Manual Type Type: Full Service Repair Manual Language Language: English Format Format: Digital (likely PDF, check product listing for specifics) 📖 Manual Coverage Systems Covered Engine: Complete engine overhaul, including disassembly, inspection, assembly, timing, valve adjustment, carburetor tuning. Transmission: Gearbox disassembly, inspection, repair, and adjustment, including clutch and final drive. Chassis And Suspension: Front fork service, shock absorber replacement, steering head bearing maintenance, swingarm bearing inspection. Brakes: Brake system servicing (drum/disc, depending on specific R90 variant), fluid replacement, caliper/master cylinder repair. Electrical System: Wiring diagrams, ignition system troubleshooting, lighting, battery, charging system (alternator/generator) repair. Fuel System: Fuel tank servicing, fuel line inspection, carburetor servicing and synchronization. Bodywork And Frame: Frame inspection, minor bodywork repair guidance, component removal and installation. Exhaust System: Inspection, repair, and replacement of exhaust components. Cooling System: While air-cooled, the manual may cover management of engine temperature and related components. Procedures Included Maintenance: Regular service checks, oil changes, filter replacements, lubrication points, tune-up procedures. Troubleshooting: Step-by-step diagnostic guides for common and uncommon issues. Repair: Detailed instructions for component repair and replacement across all major systems. Rebuild Refurbish: Comprehensive guides for engine, transmission, and other major component overhauls. Special Tools: Lists and describes the use of special tools required for specific repair procedures. Assembly Disassembly: Step-by-step instructions for complete disassembly and reassembly of all major components. Technical Depth Depth: Expert level, suitable for professional mechanics and serious enthusiasts. Covers detailed specifications, tolerances, and torque values. Diagnostic Charts: Includes comprehensive diagnostic flowcharts and symptom-based troubleshooting tables. Torque Specifications: Detailed torque specifications for all critical fasteners. 📊 Manual Specifications File Format File Type: Digital (likely PDF) Searchability: Digital PDFs are typically searchable, allowing for quick access to specific information. Print Quality Quality: High resolution scans ensuring legibility of diagrams and text. Binding Type Binding: Not applicable for digital format; if printed, would be a professional binding. Paper Type Paper: Not applicable for digital format; if printed, would be durable workshop paper. ⚙️ Engine Specifications Primary Engine Engine Type: Air-cooled, horizontally opposed two-cylinder boxer engine Engine Displacement: Approximately 897 cc (specific variant may vary slightly) Bore X Stroke: 90 mm x 70.6 mm (typical for R90/6, R90S) Performance Horsepower: Approximately 60-70 hp at 6500 rpm (depending on model R90/6 vs R90S) Torque: Approximately 75 Nm at 5000 rpm (depending on model) Fuel System Carburetors: Typically dual Dell'Orto or Bing carburetors (e.g., 32mm or 36mm) Ignition System Ignition Type: Battery-coil ignition, possibly with electronic ignition conversion options discussed. Cooling Cooling Method: Air-cooled Engine Layout Layout: Horizontally opposed (boxer) Valvetrain Valvetrain Type: Overhead valves (OHV), pushrod actuated. 🔧 Transmission Standard Transmission Type: 5-speed constant mesh gearbox Final Drive: Shaft drive Features Clutch Type: Dry single-plate or multi-plate clutch (depending on specific model variant) Gear Ratios: Detailed gear ratios provided in the manual for optimal performance tuning. 📐 Dimensions Exterior Wheelbase: Approximately 1465 mm (146.5 cm or 57.7 inches) Length: Approximately 2180 mm (218 cm or 85.8 inches) Weights Dry Weight: Approximately 200 kg (440 lbs) for R90/6, R90S might be slightly different. 🛡️ Safety Features Ratings Safety Standards: Designed to meet 1990s European safety standards for motorcycles. Active Features Braking System: Disc brakes (front and rear on R90S, typically front disc and rear drum on R90/6) with dual-circuit hydraulic system. Passive Features Frame Construction: Robust steel tube frame designed for stability and rider comfort. 💡 Technology Features Infotainment Infotainment System: N/A (Classic motorcycle, basic instrumentation only). Driver Assistance Assistance Features: N/A (Classic motorcycle). Connectivity Connectivity Options: N/A (Classic motorcycle). 🔧 Maintenance Service Intervals Oil Change Interval: Typically every 3,000-5,000 km or annually. Specific interval detailed in manual. Valve Adjustment Interval: Recommended every 5,000-10,000 km. Precise interval and procedure covered in manual. Fluid Specifications Engine Oil Type: SAE 20W-50 or SAE 10W-40 motorcycle specific oil is common. Refer to manual for exact BMW recommendation. Gearbox Oil Type: Hypoid gear oil, e.g., SAE 80W-90. Manual will specify precise grade. Brake Fluid Type: DOT 3...