🏷️ Basic Information Identification Make: BMW Model: R90 Model Designation: R90/6 Model Notes: This manual primarily covers the R90/6 model, although BMW often used the R90 designation broadly for related models. Codes Chassis Code: 247 Engine Code: 247 👋 Introduction Market Position Category: Premium Motorcycle Segment Target Audience: Enthusiasts, owners, and independent mechanics seeking detailed repair and maintenance information for classic BMW motorcycles. Competitive Analysis Key Competitors: Moto Guzzi V-twin models, Ducati V-twin models, other large-displacement European and Japanese motorcycles of the era. Key Features Distinctive Elements: Shaft drive, boxer twin engine, robust build quality, touring capability, classic styling. Manual Value Proposition: Provides essential, in-depth knowledge for preserving and maintaining a significant piece of BMW motorcycle history, empowering owners with the ability to perform complex tasks. 📋 Manual Details Coverage Areas Years Covered: 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996 Model Variants Covered: All R90 variants, primarily R90/6, potentially including closely related R90S model specifics if shared by design. Page Count Estimated Pages: Over 300 pages (typical for comprehensive service manuals of this era) Manual Type Type: Service and Repair Manual Language Language: English Format Format: Downloadable PDF 📖 Manual Coverage Systems Covered Engine: Complete engine overhaul, tuning, component diagnosis (e.g., cylinders, pistons, crankshaft, camshaft, valve train, timing chain, oil pump). Fuel System: Carburetor service (e.g., Bing CV), fuel pump, fuel lines, fuel tank, fuel filter replacement. Transmission: Gearbox disassembly, assembly, inspection, lubrication, clutch service (dry clutch for R90S, wet clutch for R90/6), drive shaft, final drive. Electrical System: Ignition system (breaker points, coils, spark plugs), lighting, charging system (alternator, voltage regulator), starter motor, battery, wiring diagrams, switches, fuses. Brakes: Front and rear brake systems (dual front discs for R90/6, single disc for R90S), master cylinder, brake lines, calipers, brake pad replacement, brake fluid service. Suspension And Steering: Front fork (conventional telescopic) overhaul, rear shock absorber replacement, swingarm bearings, steering head bearings, wheel bearings. Chassis And Bodywork: Frame inspection, seat, fuel tank removal/installation, fenders, exhaust system, side stand, center stand. Procedures Included Maintenance: Routine checks, oil changes, filter replacements, spark plug tuning, valve clearance adjustment, brake bleeding, lubrication points. Troubleshooting: Diagnostic charts for common problems, identifying causes of poor performance, starting issues, electrical faults. Repair: Step-by-step instructions for component replacement, major overhauls, and system repairs. Technical Specifications: Torque values, clearances, fluid capacities, electrical resistance values, ignition timing settings. Technical Depth Depth: Comprehensive: Covers everything from basic owner maintenance to full engine and transmission rebuilds, electrical system diagnostics, and chassis overhauls. 📊 Manual Specifications File Format File Type: PDF Searchability: Likely text-searchable (depending on original scan quality) Print Quality Resolution: Variable, but assumed to be clear enough for technical information display and printing. Binding Type Type: N/A (Downloadable Digital Format) Paper Type Type: N/A (Digital Format) ⚙️ Engine Specifications Primary Engine Type: Air-cooled, four-stroke, horizontally opposed twin-cylinder boxer engine Displacement: 900 cc (actual displacement for R90/6 is 897 cc) Bore X Stroke: 90 mm x 70.6 mm Compression Ratio: 8.2:1 (R90/6) Performance Horsepower: 60 hp (44 kW) at 6500 rpm (R90/6) Torque: 75 Nm (55 lb-ft) at 5500 rpm (R90/6) Fuel System Carburetors: 2 x Bing 32/32 mm CV (Constant Velocity) carburetors (R90/6) Fuel Type: Unleaded premium gasoline Lubrication Oil Capacity: Approx. 3.0 liters (including filter) Oil Filter Type: Spin-on cartridge (e.g., Mann-Filter W 712/3 or equivalent) 🔧 Transmission Standard Type: 5-speed manual gearbox Drive: Shaft drive to rear wheel Features Clutch Type: Single dry plate clutch (R90S), Single wet multi-plate clutch (R90/6) Final Drive Ratio: Typically 32/11 or 33/11 depending on model variant and intended use. Transmission Oil Capacity: Approx. 1.3 liters Transmission Oil Spec: SAE 75W/90 API GL-5 gear oil 📐 Dimensions Exterior Length: Approx. 2180 mm (R90/6) Width: Approx. 750 mm (handlebar width) Height: Approx. 1170 mm (seat height) Weights Dry Weight: Approx. 200 kg (R90/6) Gross Vehicle Weight: Approx. 400 kg Cargo Fuel Tank Capacity: 24 liters (including 3.5-liter reserve) 🛡️ Safety Features Ratings Crash Test Data: N/A (Motorcycle safety ratings were not standardized in the same way as cars during this era.) Active Features Braking System: Dual front disc brakes (R90/6), single rear disc brake. Effective stopping power for the era. Passive Features Frame Design: Steel tube duplex cradle frame providing rigidity and stability. Lighting: Halogen headlamp, taillight, turn signals. 💡 Technology Features Infotainment System Type: N/A (Focus on mechanical and electrical systems for this era of motorcycle. No integrated infotainment). 🔧 Maintenance Service Intervals Oil Change Interval: Every 5,000 km or annually, whichever comes first. Valve Clearance Check: Every 10,000 km or as specified in the manual. Spark Plug Replacement: Every 10,000 - 15,000 km, or based on condition. Brake Fluid Flush: Every 2 years. Fluid Specifications Engine Oil Spec: SAE 20W/50 or 10W/40 API SG or higher (check manual for specific recommendations...