🏷️ Basic Information Identification Make: BMW Model: R90 Year: 1990 Codes Engine Code: Likely R90/6 or R90S variant, specific code not provided but expected to be a 2-valve Boxer twin 👋 Introduction Market Position Target Audience: BMW R90 owners and independent mechanics seeking in-depth repair and maintenance information. Value Proposition: Enables comprehensive DIY maintenance, repair, and restoration, saving on dealership costs and preserving vehicle integrity. Competitive Analysis Comparison To Other Manuals: Positioned as a 'full service' manual, implying greater depth than basic owner's manuals or condensed workshop guides. Key Features Diagnostic Emphasis: Highlights diagnostic capabilities, suggesting it aids in identifying and resolving problems efficiently. Restoration Focus: Explicitly mentions refurbishment and restoration, catering to owners looking to bring classic bikes back to life. 📋 Manual Details Coverage Areas Manual Type: Full Service and Repair Manual Language: English Format: Digital (likely PDF) Page Count Estimated Page Count: Likely 400-600 pages based on comprehensiveness, exact count not provided 📖 Manual Coverage Systems Covered Engine Overhaul: Complete engine disassembly, inspection, repair, and reassembly procedures for the BMW boxer twin engine. Fuel System: Carburetor tuning (likely Dell'Orto or Bing), fuel pump, fuel lines, and fuel tank maintenance. Ignition System: Spark plugs, ignition coils, timing adjustment, and troubleshooting for the ignition circuit. Transmission And Drivetrain: Gearbox inspection, repair, clutch service, driveshaft maintenance, and final drive unit procedures. Suspension And Steering: Front forks (likely dual shock absorber or Monolever rear), rear suspension components, wheel bearing replacement, and steering head bearing adjustment. Brakes: Front and rear brake system servicing, including caliper overhaul, pad replacement, brake fluid bleeding, and master cylinder inspection. Electrical System: Wiring diagrams, battery maintenance, lighting system troubleshooting, starter motor and alternator servicing. Frame And Bodywork: Chassis inspection, body panel removal and installation, seat mounting, and exhaust system maintenance. Procedures Included Routine Maintenance: Oil changes, filter replacements, chain adjustment, tire pressure checks, and general lubrication. Troubleshooting: Diagnostic flowcharts and common problem identification for various systems. Rebuilding: Detailed instructions for rebuilding major components like the engine, gearbox, and forks. Refurbishment Restoration: Guidance on restoring components and bringing the motorcycle back to its original condition. Technical Depth Diagnostic Procedures: Includes diagnostic steps for identifying issues within the electrical, fuel, and mechanical systems. Technical Specifications: Comprehensive torque values, clearances, fluid capacities, and other critical technical data. Component Level Repair: Detailed instructions for repairing individual components rather than just replacement. 📊 Manual Specifications File Format File Type: Digital (likely PDF) Searchability: Expected to be searchable text for easy information retrieval. Print Quality Image Resolution: High-resolution diagrams and illustrations for clarity. Binding Type Binding: N/A (Digital Format) Paper Type Paper Quality: N/A (Digital Format) ⚙️ Engine Specifications Primary Engine Engine Type: Air-cooled, four-stroke, boxer-twin cylinder engine Engine Displacement: 897 cc (54.7 cubic inches) Bore X Stroke: 90 mm x 70.6 mm (approximately, common for R90 variants) Compression Ratio: Typically 9.5:1 (R90/6) or 10.25:1 (R90S), specific to variant. Performance Horsepower Output: R90/6: 60 hp @ 6500 rpm; R90S: 67 hp @ 7000 rpm (approximate, specific to variant). Torque Output: R90/6: 75 Nm @ 5500 rpm; R90S: 77 Nm @ 5500 rpm (approximate, specific to variant). Fuel System Carburetors: Dual Dell'Orto PHM 38 (R90/6) or Bing 32mm CV carburetors (R90S). Fuel Type Recommendation: Unleaded gasoline, minimum octane rating typically 91 RON (95 AKI). Engine Internals Valve Train: Overhead valve (OHV) with pushrods and rocker arms. 🔧 Transmission Standard Transmission Type: 5-speed manual gearbox, shaft drive. Clutch Type: Single dry plate, diaphragm spring clutch. Features Gear Ratios: Specific ratios will be detailed in the manual, typically optimized for touring and sport riding. Fluid Specifications Transmission Oil Type: SAE 80W/90 GL-4 gear oil recommended. Fluid Capacity Transmission Oil Capacity: Approximately 1.2 liters (1.3 US quarts). 📐 Dimensions Exterior Wheelbase: Approximately 1465 mm (57.7 inches). Seat Height: Approximately 800-820 mm (31.5-32.3 inches), depending on seat and suspension. Weights Dry Weight: Approximately 205-210 kg (452-463 lbs). Gross Vehicle Weight Rating: Not specified, but owner should consult manual for safe load limits. Fuel Capacity Fuel Tank Capacity: 24 liters (6.3 US gallons), including a reserve of approx. 3 liters. 🛡️ Safety Features Ratings Crash Test Information: Motorcycles of this era were not subjected to standardized crash testing like modern automobiles. Active Features Braking System: Dual disc front brake, single disc rear brake (standard on R90S, optional on R90/6). Brake calipers typically by Brembo. Suspension System: Telescopic front forks and a rear swingarm with dual shock absorbers (or Monolever system on later models, R90 was typically dual shock). Provides stability and handling. Passive Features Lighting System: Halogen headlamp, taillight, brake light, and turn signals for visibility. 💡 Technology Features Infotainment Infotainment Systems: N/A - This motorcycle predates integrated infotainment systems. Focus is on core mechanical and electrical functions. Driver Assistance Driver Assistance Features: N/A - No electronic driver assistance features are present on this model. Connectivity Connectivity Features: N/A...