Model:
R Series (R80, R90, R100)
Chassis Code R80:
Various, often associated with the R80/7, R80ST, R80GS, R80RT variants
Chassis Code R90:
Various, often associated with the R90/6, R90S variants
Chassis Code R100:
Various, often associated with R100/7, R100S, R100RS, R100RT, R100GS, R100R variants
Target Audience:
Professional motorcycle technicians, experienced DIY mechanics, and BMW R Series enthusiasts seeking comprehensive repair guidance.
Advantage:
Provides detailed, model-specific information for a range of R Series models from a particular year, often consolidating information from various BMW factory publications into a single, accessible resource.
Features:
Instant download, comprehensive coverage, professional technician focus, detailed diagrams and specifications.
Engine Coverage:
Detailed diagnosis, repair, and overhaul procedures for boxer twin engines
Transmission Coverage:
Service and repair of 4-speed and 5-speed transmissions, including clutch and final drive
Chassis Coverage:
Suspension (forks, shock absorbers), steering, braking systems, and wheel assembly
Electrical Coverage:
Wiring diagrams, ignition system, lighting, charging system (alternator, regulator), starter motor, and instrumentation
Bodywork Coverage:
Frame, fuel tank, seat, fenders, fairings (if applicable), and accessory mounting
Estimated Page Count:
Likely 300-500+ pages, typical for a comprehensive service manual
Manual Type:
Repair and Service Manual
Engine Systems:
Cylinder head, valve train, pistons, connecting rods, crankshaft, lubrication system, cooling (air-cooled), fuel delivery (carburetors/fuel injection), exhaust system, ignition system
Transmission Systems:
Gearbox, clutch assembly (single-plate dry, later dual-plate), driveshaft, final drive unit (bevel gear)
Suspension Steering Systems:
Telescopic forks (monolever and paralever variations), rear swingarm, shock absorbers, steering head bearings
Braking Systems:
Disc brakes (front and rear), brake fluid, calipers, master cylinders, brake lines
Electrical Systems:
Bosch ignition, dynamo/alternator, regulator, starter motor, battery, lighting circuits, instrumentation, horn
Maintenance Procedures:
Oil changes, filter replacement, spark plug service, valve clearance adjustment, carburetor synchronization, battery maintenance, brake pad replacement, chain/driveshaft lubrication
Diagnostic Procedures:
Troubleshooting common starting, running, and electrical issues, component testing
Repair Procedures:
Engine rebuild (top and bottom end), transmission overhaul, fork seal replacement, shock absorber replacement, brake caliper overhaul, starter motor repair, alternator/regulator testing and replacement
Adjustments:
Carburetor jetting and synchronization, ignition timing, clutch play, throttle cable adjustment, brake lever free play
Torque Specifications:
Comprehensive torque values for all critical fasteners and components
Depth:
Designed for professional technicians, providing in-depth mechanical and electrical repair procedures, including component disassembly, inspection, repair, and reassembly. Covers advanced diagnostics and specifications beyond basic owner's manual information.
Searchability:
Likely text-searchable PDF, enabling quick navigation to specific topics
Image Resolution:
Typically good, with clear line drawings, diagrams, and photographs suitable for printing
Binding:
N/A (Digital PDF Download)
Paper Type:
N/A (Digital PDF Download)
Engine Type:
Air-cooled, four-stroke boxer twin cylinder
Bore Stroke R80:
Approx. 82 mm x 74.5 mm (varies by specific R80 variant)
Bore Stroke R90:
Approx. 90 mm x 70.6 mm (varies by specific R90 variant)
Bore Stroke R100:
Approx. 94 mm x 70.6 mm (varies by specific R100 variant)
Displacement R80:
Approx. 797 cc to 800 cc
Displacement R90:
Approx. 897 cc to 900 cc
Displacement R100:
Approx. 979 cc to 1000 cc
Horsepower R80:
Approx. 50-60 HP (varies by model)
Horsepower R90:
Approx. 65-70 HP (varies by model)
Horsepower R100:
Approx. 65-70 HP (varies by model)
Torque R80:
Approx. 60-70 Nm
Torque R90:
Approx. 75-80 Nm
Torque R100:
Approx. 75-80 Nm
Carburetors:
Typically Bing slide-type carburetors (e.g., 32mm, 36mm, 40mm depending on model and year)
Fuel Injection:
Later models may feature Bosch L-Jetronic or Motronic fuel injection (less common on 1991 models, but covered if applicable to specific R100 variants)
Ignition Type:
Mechanical contact breaker points (older models) or electronic ignition (later models, e.g., breakerless systems)
Transmission Type:
5-speed manual gearbox
Optional Gearbox:
Some earlier models featured 4-speed gearboxes, but 1991 models primarily use 5-speed.
Drive System:
Shaft drive (via driveshaft and bevel gear final drive)
Clutch Type:
Single-plate dry clutch (most models) or optional dual-plate dry clutch on higher performance variants.
Gear Ratios:
Specific gear ratios are detailed within the manual for each model variant.
Wheelbase Typical:
Approx. 1440 mm - 1500 mm (varies significantly by model variant - R, RS, RT, GS, R80ST, etc.)
Dry Weight Typical:
Approx. 190 kg - 230 kg (varies significantly by model variant)
Fuel Tank Capacity Typical:
Approx. 19-24 liters (varies by model - e.g., RT models had larger tanks)
Safety Features Design:
Designed with robust chassis and reliable mechanical components. Specific crash ratings are not applicable to this era of motorcycle in the same way as modern automobiles.
Braking System:
Dual front disc brakes, single rear disc brake (on most models). ABS was not commonly available on these models in 1991.
Lighting System:
Halogen headlight, integrated turn signals and taillight.
Oil Change Interval:
Typically every 5,000-10,000 km or annually, depending on usage. Manual will specify exact intervals.
Valve Adjustment Interval:
Typically every 10,000-20,000 km. Manual will provide precise intervals.
Spark Plug Replacement Interval:
Variable, often around 10,000-20,000 km. Manual will advise.
Engine Oil Type:
API SF/SG or higher, SAE 20W-50 or 10W-40 depending on climate. Manual will specify exact grade.
Engine Oil Capacity:
Approx. 2.5 - 3.0 liters with filter change. Manual will specify.
Transmission Oil Type:
Gear oil, e.g., SAE 75W-90 or 80W-90. Manual will specify.
Final Drive Oil Type:
Gear oil, e.g., SAE 80W-90. Manual will specify.
Brake Fluid Type:
DOT 3 or DOT 4 brake fluid. Manual will specify exact type and replacement interval.
Common Wear Items:
Clutch wear, exhaust pipe leaks, swingarm pivot bearings, steering head bearings, rear drive splines, ignition coils, voltage regulator failures.
Carburetor Issues:
Pilot jet clogging, vacuum leaks, carburetor synchronization drift.
Heritage Notes:
BMW Motorrad has a long and distinguished history dating back to the early 20th century, renowned for engineering excellence, reliability, and boxer engine technology.
R Series Evolution:
The R Series boxer twins are an iconic lineage, evolving from the R32 in 1923. The R80, R90, and R100 models represent significant developments, including the introduction of the Monolever and Paralever rear suspension systems and advancements in engine management and braking.
Production Era:
These specific R Series models were primarily produced from the late 1970s through the 1980s and into the early 1990s, with 1991 representing a later iteration of these established platforms.
