🏷️ Basic Information Identification Make: BMW Model: R90 Year: 1983 Codes Engine Code: R90/6 (for the R90S, but often associated with the R90 moniker; the R90 was primarily known as the R90/6 and R90S) 👋 Introduction Market Position Positioning: The BMW R90 series represented BMW's entry into the larger displacement motorcycle market, known for its robust engineering and touring capabilities. Competitive Analysis Competitors: Competed with other European and Japanese motorcycles offering similar displacement and touring features, though BMW's shaft drive and boxer engine configuration offered unique advantages. Key Features Distinctive Features: Shaft drive, air-cooled flat-twin boxer engine, robust build quality, comfortable ergonomics for long-distance riding, particularly the R90S with its sportier fairing and dual front discs. 📋 Manual Details Coverage Areas Primary Coverage: Comprehensive service and repair for BMW R90 models Secondary Coverage: Maintenance, troubleshooting, diagnostics, electrical systems, engine overhaul, transmission repair, chassis and suspension work, bodywork. Specific Models Covered: BMW R90/6 and BMW R90S Page Count Estimated Page Count: 350-450 Manual Type Type: Service and Repair Manual Language Language: English Format Format: Digital Download (PDF) 📖 Manual Coverage Systems Covered Engine: Detailed disassembly, assembly, inspection, and overhaul procedures for the BMW flat-twin boxer engine. Fuel System: Carburetor service (Dell'Orto PHM 40 CS), fuel tank, fuel lines, fuel pump, fuel filter. Ignition System: Points, condenser, ignition coils, spark plugs, timing adjustments, electronic ignition options (if applicable to '83). Transmission: Gearbox inspection, lubrication, repair, clutch operation and adjustment, final drive assembly. Electrical System: Wiring diagrams, battery, charging system (alternator, regulator), lighting, starter motor, instrument cluster, horn. Brakes: Front and rear brake systems, brake fluid specifications, caliper service, master cylinder, brake lines, pad replacement. Suspension Steering: Front forks (oil change, seal replacement), rear shock absorbers, swingarm, steering head bearings, wheel bearings. Chassis Bodywork: Frame inspection, seat, fuel tank mounting, fenders, exhaust system, general body component removal/installation. Procedures Included Maintenance: Routine servicing, oil changes, filter replacements, lubrication points, chain adjustment, spark plug replacement. Troubleshooting: Diagnostic guides for common running issues, electrical faults, starting problems. Repair: Step-by-step instructions for engine rebuild, transmission overhaul, brake system repair, electrical component replacement. Adjustments: Carburetor synchronization and tuning, ignition timing, clutch and throttle cable adjustments, valve clearance checks. Wheel Service: Wheel bearing replacement, spoke tensioning (if applicable), tire mounting and balancing. Exhaust System Repair: Inspection, gasket replacement, muffler repair or replacement. Body Panel Removal: Detailed procedures for removing fuel tank, side covers, fenders, seat, and headlight assembly. Technical Depth Depth: Comprehensive, suitable for experienced home mechanics and professional technicians. Covers from basic maintenance to complete engine and transmission rebuilds. Specific Rebuilds: Complete engine rebuild including piston and cylinder service, crankshaft inspection, camshaft and valve train overhaul. Diagnostic Charts: Troubleshooting charts correlating symptoms with potential causes and corrective actions for engine, electrical, and chassis issues. 📊 Manual Specifications File Format File Format: PDF Searchability: Searchable text for quick information retrieval Printability: Printable pages for hands-on use in the workshop Print Quality Image Resolution: High-resolution images and diagrams for clarity Binding Type Binding Type: N/A (Digital Download) Paper Type Paper Type: N/A (Digital Download) ⚙️ Engine Specifications Primary Engine Engine Type: Air-cooled, four-stroke, flat-twin boxer Displacement: 897 cc Bore X Stroke: 90 mm x 70.6 mm Compression Ratio: 9.5:1 (R90S), 8.2:1 (R90/6) Performance Horsepower: 67 hp (49 kW) at 7,000 rpm (R90S), 55 hp (40 kW) at 6,200 rpm (R90/6) Torque: 77 Nm (57 lb-ft) at 5,500 rpm (R90S), 75 Nm (55 lb-ft) at 5,000 rpm (R90/6) Fuel System Carburetors: 2 x Dell'Orto PHM 40 CS (R90S), 2 x Bing 32mm (R90/6) Fuel Capacity: 24 liters (6.3 US gal) 🔧 Transmission Standard Type: 5-speed constant mesh gearbox Final Drive: Shaft drive Features Clutch: Single dry plate, diaphragm spring clutch 📐 Dimensions Exterior Length: Approx. 2200 mm (86.6 in) Width: Approx. 800 mm (31.5 in) at handlebars Height: Approx. 1150 mm (45.3 in) to top of handlebars Weights Dry Weight: Approx. 215 kg (474 lbs) Gross Vehicle Weight: Approx. 420 kg (926 lbs) 🛡️ Safety Features Ratings Crash Test Ratings: N/A (Motorcycle, pre-dates standardized motorcycle crash testing) Active Features Braking: Dual front disc brakes (R90S), Single front disc brake (R90/6), Rear drum brake. Hydraulic actuation. Lighting: Halogen headlight, taillight, brake light, turn signals. Passive Features Frame: Steel tube duplex cradle frame providing robust structural integrity. 💡 Technology Features Infotainment Infotainment System: N/A (Analog instrumentation typical for the era) 🔧 Maintenance Service Intervals Oil Change Interval: Every 5,000 km (3,000 miles) or annually Valve Adjustment Interval: Every 10,000 km (6,000 miles) Spark Plug Replacement Interval: Every 10,000 km (6,000 miles) Fluid Specifications Engine Oil Type: SAE 20W-50 or SAE 15W-40 (API SE/SF recommended for modern equivalents) Engine Oil Capacity: 2.5 liters (2.6 US qt) with filter change Transmission Oil Type: SAE 80W-90 GL-4 Gear Oil Final Drive Oil Type: SAE 80W-90 GL-5 Gear Oil Brake Fluid Type: DOT 3 or DOT 4...