🏷️ Basic Information Identification Make: BMW Model: R90 Year: 1987 Codes Engine Code Identifier: R90/6 (typically refers to the 898cc boxer engine) 👋 Introduction Market Position Segment: Classic BMW Airhead Motorcycle segment Competitive Analysis Competitors: Manuals for other contemporary large-displacement motorcycles, but specifically targeting BMW R series enthusiasts. Key Features Manual Value: Authoritative guide for preserving and restoring a classic BMW motorcycle. Content Emphasis: Focus on detailed procedures, diagnostic information, and technical specifications crucial for accurate repairs and maintenance. 📋 Manual Details Coverage Areas Primary Coverage: Full Service, Repair, Maintenance, Rebuild, Refurbishment, Restoration Page Count Estimated Page Count: Likely over 400 pages (typical for comprehensive BMW motorcycle service manuals) Manual Type Type: Full Service and Repair Manual Language Language: English Format Format: Likely Digital (PDF) given description, potentially printable Searchability: Searchable text for quick information retrieval (typical for high-quality digital manuals). Printability: Printable pages for workshop use. 📖 Manual Coverage Systems Covered Engine Mechanical: Engine overhaul, cylinder head repair, piston replacement, valve adjustment, crankshaft and connecting rod inspection, timing chain/belt maintenance. Fuel System: Carburetor tuning and rebuilding (e.g., Bing carburetors), fuel pump inspection and repair, fuel tank and lines maintenance. Ignition System: Ignition timing adjustment, spark plug inspection, coil and ignition module testing, breaker point (if applicable) maintenance. Transmission Drivetrain: Gearbox disassembly and reassembly, clutch adjustment and replacement, driveshaft and final drive inspection and servicing. Electrical System: Wiring diagrams, alternator and starter motor testing, battery maintenance, lighting system troubleshooting, horn and switchgear servicing. Braking System: Brake fluid replacement, caliper and master cylinder servicing, brake pad and disc inspection and replacement, brake line maintenance. Suspension Steering: Front fork overhaul, rear shock absorber servicing, steering head bearing adjustment, wheel bearing replacement. Frame Bodywork: Frame inspection, fairing and body panel repair, seat upholstery, exhaust system maintenance. Procedures Included Routine Maintenance: Oil changes, filter replacements, lubrication points, chain adjustment, tire pressure checks, brake adjustments. Diagnostic Troubleshooting: Step-by-step diagnostic procedures for common and uncommon issues, fault finding guides. Rebuild Procedures: Detailed instructions for complete engine, gearbox, and suspension rebuilds. Special Tools: Identification and usage of specialized tools required for specific repair procedures. Electrical Troubleshooting: Detailed wiring diagrams, component testing procedures, and common electrical fault diagnosis. Engine Diagnostics: Compression testing, ignition timing checks, fuel mixture adjustments, and identification of mechanical issues. Technical Depth Depth: Comprehensive, covering basic maintenance to complete engine rebuilds and advanced diagnostics. 📊 Manual Specifications File Format File Type: PDF (Assumed) Print Quality Print Clarity: High-resolution scans of original documentation, ensuring clear diagrams and text. Binding Type Binding: N/A (Digital Format) Paper Type Paper Quality: N/A (Digital Format) Completeness Scope Of Coverage: Comprehensive: Covers everything from routine maintenance to complete overhauls and troubleshooting for all major vehicle systems. ⚙️ Engine Specifications Primary Engine Engine Type: Air-cooled, four-stroke, horizontally opposed twin-cylinder (Boxer) Displacement: 898 cc (for R90/6 designation) Bore X Stroke: 90 mm x 70.6 mm Compression Ratio: Approximately 9.5:1 Valve Train: Overhead valves (OHV), pushrod actuated Performance Horsepower: Approx. 60 hp at 6,500 rpm (R90/6) Torque: Approx. 70 Nm (52 lb-ft) at 5,000 rpm (R90/6) Fuel System Carburetion: Dual Bing 32/40mm carburetors (common on R90/6) Fuel Type: Unleaded gasoline (premium recommended) Lubrication System Oil Capacity: Approx. 2.5 Liters (5.3 US Pints) Oil Filter Type: Internal oil screen and potentially a spin-on filter depending on exact variant/aftermarket fitment. Manual will specify. Engine Code Identifier Engine Variant: R90/6 (typically the standard model) 🔧 Transmission Standard Type: 5-speed, constant mesh, sequential manual transmission Features Clutch Type: Single dry plate, diaphragm spring Final Drive: Shaft drive Gear Ratios: Specific ratios will be detailed in the manual; typically geared for touring. Transmission Fluid Fluid Type: GL-1 or GL-4 Hypoid Gear Oil (e.g., SAE 80W/90), manual will specify exact BMW recommendation. 📐 Dimensions Exterior Wheelbase: Approx. 1465 mm (57.7 inches) Length: Approx. 2180 mm (85.8 inches) Seat Height: Approximately 820 mm (32.3 inches) Weights Dry Weight: Approx. 205 kg (452 lbs) Fuel Tank Capacity: Approx. 19 Liters (5.0 US Gallons), including reserve 🛡️ Safety Features Ratings Crash Test Data: N/A for motorcycles of this era in the context of automotive crash testing. Active Features Braking System Type: Dual front disc brakes, single rear disc brake (typical for R90/6) Passive Features Lighting: Halogen headlight, taillight, brake light, turn signals. 💡 Technology Features Infotainment Features: N/A - This era of motorcycle predates modern infotainment systems. 🔧 Maintenance Service Intervals Oil Change Interval: Typically every 5,000-7,500 km (3,000-4,500 miles) or annually. Manual will provide exact interval. Valve Adjustment Interval: Typically every 10,000-15,000 km (6,000-9,000 miles). Manual will provide exact interval. Gearbox Final Drive Oil Change: Typically every 10,000-20,000 km (6,000-12,000 miles). Manual will provide exact interval. Fluid Specifications Engine Oil: Typically SAE 20W/50 or SAE 15W/40 motorcycle-specific oil. Manual will specify exact BMW recommendation. Brake Fluid: DOT 3 or DOT 4 brake fluid (manual will specify). Final Drive Oil: SAE 80W/90 hypoid...