Target Audience:
DIY mechanics, independent repair shops, BMW motorcycle enthusiasts, owners seeking to maintain their classic Airhead BMWs.
Value Proposition:
Provides essential, in-depth technical information for servicing and repairing a range of iconic BMW boxer twins, empowering owners to perform maintenance and repairs themselves, potentially saving significant costs.
Comprehensiveness:
Covers multiple models (R80, R90, R100) and their variations from a specific, critical production year, offering broad utility.
Technical Accuracy:
Sourced from professional repair documentation, ensuring accuracy and adherence to BMW's specifications for the era.
Engine Mechanical:
Engine disassembly, assembly, inspection, valve adjustment, piston/cylinder service, crankshaft, connecting rods, timing chain.
Fuel System:
Carburetor service and adjustment (e.g., Bing CV carbs), fuel pump, fuel lines, fuel tank maintenance.
Ignition System:
Ignition timing, coil replacement, spark plug service, distributor (if applicable), electronic ignition components.
Transmission Drivetrain:
Gearbox disassembly, inspection, repair, clutch service, final drive maintenance and overhaul, driveshaft service.
Electrical System:
Wiring diagrams, starter motor, alternator, battery service, lighting system, horn, instrument cluster, fuse box.
Brakes:
Brake caliper service, master cylinder overhaul, brake line replacement, brake pad replacement, bleeding procedure, parking brake.
Suspension Steering:
Fork service (e.g., oil change, seal replacement), rear shock absorber maintenance, steering head bearing adjustment, wheel bearing service.
Frame Bodywork:
Chassis inspection, fairing removal and installation, seat maintenance, fender service, general body panel adjustments.
Preventative Maintenance:
Oil changes, filter replacements, spark plug checks, lubrication points, chain adjustment (if applicable to specific models).
Troubleshooting:
Diagnostic flowcharts for common problems related to engine performance, electrical issues, starting problems, etc.
Repair Procedures:
Step-by-step guides for engine rebuilds, transmission overhauls, suspension repairs, electrical component replacement.
Component Overhaul:
Detailed instructions for overhauling carburetors, brake calipers, starter motors, alternators, and other key components.
Wheel Tire Service:
Tire pressure checks, wheel removal/installation, spoke tensioning (for wire-spoked wheels), balancing.
Depth Level:
Comprehensive (from basic maintenance to full engine/transmission rebuilds)
Engine Type:
Air-cooled, four-stroke, horizontally opposed twin-cylinder (Boxer)
Displacement R80:
797.5 cc (approx. 800cc)
Displacement R90:
897.7 cc (approx. 900cc)
Displacement R100:
979.5 cc to 1000 cc (approx. 1000cc, depending on specific R100 variant)
Bore Stroke R80:
82.5 mm x 74.5 mm
Bore Stroke R90:
90 mm x 70.6 mm
Bore Stroke R100:
94 mm x 74.5 mm (typical for R100/7, RS, RT, CS)
Horsepower R80:
Approx. 50-55 hp @ 6500 rpm (varies by model)
Horsepower R90:
Approx. 60-66 hp @ 7000 rpm (varies by model)
Horsepower R100:
Approx. 65-70 hp @ 7250 rpm (varies by model)
Torque R80:
Approx. 57-60 Nm @ 5000 rpm
Torque R90:
Approx. 70-75 Nm @ 5500 rpm
Torque R100:
Approx. 74-80 Nm @ 6000 rpm
Carburetion:
Typically twin Bing Constant Velocity (CV) carburetors (e.g., 32mm or 40mm depending on model and year).
Fuel Type:
Unleaded gasoline, minimum 91 RON (Research Octane Number) or equivalent.
Fuel Delivery:
Gravity feed from fuel tank via fuel tap and lines.
Oil Change Interval:
Typically every 5,000 km (3,000 miles) or annually. Manual will specify precise interval and oil grade.
Valve Adjustment Interval:
Recommended every 10,000 km (6,000 miles). Essential for engine health and performance.
Major Service Interval:
Comprehensive checks and potential component overhauls recommended around every 40,000-50,000 km (25,000-30,000 miles).
Engine Oil Spec:
SAE 20W/50 or SAE 10W/40 motorcycle-specific oil (API SG or higher). Check manual for precise viscosity and API rating.
Engine Oil Capacity:
Approx. 2.5 - 3.0 liters (2.6 - 3.2 US quarts) depending on model and oil filter change.
Brake Fluid Spec:
DOT 3 or DOT 4 brake fluid (check manual for specific recommendation).
Common Wear Items:
Clutch wear, fork seal leaks, steering head bearing play, starter motor brushes, final drive splines wear.
Carburetor Issues:
Sticking slides, worn diaphragms, difficult synchronization between carburetors can lead to rough idling and poor performance.
Electrical Reliability:
While generally robust, older wiring harnesses can degrade. Intermittent electrical faults can occur. Charging system components (rectifier/regulator) can be a point of failure.
Manufacturer Origin:
Bayerische Motoren Werke AG (BMW), Germany.
Motorcycle Legacy:
BMW has a long and distinguished history in motorcycle manufacturing, dating back to 1923, renowned for its robust engineering and boxer engines.
Airhead Development:
The R80, R90, and R100 series are part of BMW's long-running 'Airhead' boxer motorcycle lineage, which evolved from the R50 series through numerous iterations, emphasizing reliability, shaft drive, and touring capability.
Production Period:
The 'slash 7' generation, including the R80/7, R100/7, R100RS, R100RT, and their successors, were produced from the mid-1970s through the 1980s. The 1983 model year represents a mature stage of this design, incorporating incremental improvements.
Manufacturing Location:
Primarily manufactured in Berlin, Germany, at BMW's motorcycle plant.
