Model:
R Series (R80, R90, R100)
Year Coverage:
Primarily 1990, with relevant data for similar model years within the R Series family.
Engine Code:
Various boxer-twin configurations (e.g., R80 series: 797cc, R90 series: 897cc, R100 series: 980cc, 1000cc variants)
Target Audience:
Professional motorcycle technicians, experienced DIY mechanics, and BMW R Series enthusiasts.
Value Proposition:
Provides essential technical data for maintaining and repairing a classic BMW motorcycle range, crucial for preserving longevity and performance.
Comprehensiveness:
Covers a wide spectrum of repair and maintenance tasks, essential for owners who perform their own servicing.
Authoritative Source:
Prepared for professional technicians, indicating a high level of technical accuracy and detail.
Engine Overhaul:
Complete engine disassembly, inspection, repair, and reassembly procedures for boxer-twin engines.
Transmission Service:
Gearbox (5-speed manual) removal, disassembly, repair, and reassembly, including clutch service.
Electrical System:
Wiring diagrams, component testing, ignition system, charging system (alternator/generator), lighting, starter motor.
Fuel System:
Carburetor (often Bing) service, fuel tank, fuel lines, and fuel pump (if applicable).
Braking System:
Hydraulic brake system (disc front, drum/disc rear depending on model), including caliper, master cylinder, and fluid service.
Suspension And Steering:
Front fork (telescopic), rear swingarm, shock absorbers, steering head bearings, and wheel bearing service.
Exhaust System:
Removal, installation, and inspection of exhaust headers and mufflers.
Frame And Bodywork:
Chassis inspection, side stand, center stand, fuel tank, seat, fenders, and minor body panel repair.
Routine Maintenance:
Oil changes, filter replacement, spark plug service, valve adjustment, chain lubrication (if applicable), tire pressure checks.
Troubleshooting Guides:
Diagnostic procedures for common starting, running, and electrical issues.
Major Repairs:
Engine rebuilds, transmission overhauls, suspension component replacement, brake caliper rebuilding.
Torque Specifications:
Detailed torque values for critical fasteners across all major components.
Diagnostic Capability:
Designed for professional technicians, providing in-depth diagnostic flowcharts and component testing procedures.
Rebuild Instructions:
Comprehensive instructions for complete engine, transmission, and major system rebuilds.
Special Tool Requirements:
Likely lists necessary special tools required for specific repair procedures.
Engine Type:
Air-cooled, four-stroke, horizontally opposed twin-cylinder (Boxer)
Bore Stroke R80:
Approx. 82.5 mm x 75 mm
Bore Stroke R90:
Approx. 90 mm x 70.5 mm
Bore Stroke R100:
Approx. 94 mm x 70.5 mm (R100/7, R100S) or 94mm x 74.5mm (R100RT, R100RS)
Compression Ratio R80:
Approx. 8.2:1
Compression Ratio R100:
Approx. 8.5:1 to 9.5:1 (model dependent)
Horsepower R80:
Approx. 50-55 HP @ 6200-7000 RPM
Horsepower R100:
Approx. 65-70 HP @ 7000-7250 RPM
Torque R80:
Approx. 58-62 Nm @ 4500-5000 RPM
Torque R100:
Approx. 70-75 Nm @ 5000-5500 RPM
Carburetors:
Typically dual Bing constant-velocity carburetors (e.g., 32mm or 40mm depending on model).
Fuel Type:
Unleaded gasoline, minimum 91-95 RON (Octane rating may vary by specific model/tuning).
Wheelbase:
Varies by model, typically around 1440-1480 mm.
Seat Height:
Varies by model, often around 780-820 mm.
Dry Weight:
Approx. 200-230 kg (depending on model and equipment).
Gross Vehicle Weight Rating:
Approx. 390-420 kg.
Crash Test Data:
Not applicable for motorcycles of this era in the same way as cars.
Braking System Type:
Hydraulic disc brakes front (often dual discs on R100 models), drum or disc rear.
Suspension Damping:
Telescopic front fork with adjustable damping (on some models), twin rear shock absorbers with adjustable pre-load.
Lighting:
Halogen headlamp, tail lamp, brake light, turn signals.
Oil Change Interval:
Typically every 3,000-5,000 miles or annually, whichever comes first. Specific interval for gearbox oil and final drive oil also detailed.
Valve Adjustment Interval:
Often at 6,000-12,000 mile intervals, depending on model and usage.
Spark Plug Replacement:
Recommended every 6,000-12,000 miles. Manual will specify gap and type.
Engine Oil Type:
API SG or higher, SAE 20W-40 or 20W-50 recommended (consult manual for precise viscosity based on climate).
Engine Oil Capacity:
Approx. 2.5 - 3.0 liters (including filter).
Gearbox Oil Type:
GL-5 80W/90 gear oil.
Gearbox Oil Capacity:
Approx. 1.0 - 1.2 liters.
Brake Fluid Type:
DOT 3 or DOT 4 hydraulic brake fluid.
Common Wear Items:
Seals (engine, transmission, fork), clutch plates, ignition points (on older models), swingarm pivot bearings, steering head bearings.
Electrical Gremlins:
Wiring harness wear, charging system issues (voltage regulator, alternator brushes), starter solenoid problems are not uncommon.
Engine Idling Instability:
Can often be traced to carburetor synchronization, jetting issues, or air leaks.
Bmw Motorrad Legacy:
BMW Motorrad has a long history of engineering robust and reliable motorcycles, particularly known for its boxer-twin engine configuration and shaft drive.
R Series Development:
The R80, R90, and R100 series represent a significant evolution of BMW's boxer twins, building upon earlier models like the R50, R60, R75, and R90/6. These models offered increased displacement, improved performance, and refined chassis components.
R100 Variants:
The R100 line included various models such as the R100/7, R100S, R100RS (full fairing), R100RT (touring), R100GS (dual-sport), and R100R (roadster).
Manufacturing Era:
The R80, R90, and R100 series were predominantly produced from the mid-1970s through the 1980s and into the early 1990s. The 1990 model year signifies the later stages of this influential generation.
