Segment:
Classic Airhead BMW Motorcycles
Target User Base:
Owners of BMW R80, R90, and R100 series motorcycles, particularly those manufactured around 1990. Also valuable for independent repair shops specializing in vintage BMWs.
Manual Value:
Provides indispensable, factory-level repair and maintenance data, crucial for preserving the functionality and value of these iconic motorcycles. Replaces or supplements less detailed informal guides.
Authenticity:
Represents professional-grade information trusted by mechanics worldwide for accurate repairs.
Comprehensiveness:
Covers a wide range of service, repair, and troubleshooting procedures.
Engine Mechanical:
Complete overhaul, component inspection, assembly, tuning, torque specifications
Engine Electrical:
Ignition system (points, electronic), charging system (alternator, regulator), starting system, wiring diagrams
Fuel System:
Carburetor overhaul (Bing), fuel tank, fuel lines, fuel pump (if applicable)
Transmission Drivetrain:
Gearbox disassembly and assembly, clutch operation, driveshaft maintenance, final drive unit
Brakes:
Hydraulic system (master cylinder, calipers, lines), brake pad replacement, bleeding procedures, drum brake adjustment (rear for some models)
Suspension:
Front fork (telescopic), rear swingarm, shock absorbers, wheel bearings
Chassis Frame:
Frame inspection, steering head bearing maintenance
Electrical Components:
Headlight, taillight, indicators, horn, battery, fuses
Routine Maintenance:
Oil changes, filter replacements, spark plug checks, valve clearance adjustment, lubrication points
Troubleshooting:
Diagnostic procedures for common performance issues, electrical faults, starting problems
Rebuilding Overhaul:
Detailed step-by-step guides for engine, transmission, and carburetor rebuilds
Adjustments:
Carburetor synchronization, idle speed, ignition timing, clutch, throttle cables
Inspection Diagnosis:
Wear limits for engine components, electrical system testing
Diagnostic Capabilities:
Advanced diagnostic procedures for identifying root causes of malfunctions
Repair Complexity:
Covers everything from basic fluid changes to complete engine and transmission rebuilds
Documentation Type:
Official factory-level service data, including exploded views, diagrams, and specifications
Format Type:
Digital (PDF)
Searchability:
Likely text-searchable if properly scanned and OCR'd, facilitating quick access to information
Image Clarity:
High-resolution scans of original diagrams and photographs are essential for clarity
Binding Style:
N/A (Digital format)
Paper Quality:
N/A (Digital format)
Coverage Scope:
Comprehensive, covering all major mechanical and electrical systems relevant to the specified models and year
Engine Type:
Air-cooled, four-stroke, horizontally opposed boxer twin-cylinder
Displacement R80:
797.5 cc (48.6 cu in)
Displacement R90:
897.9 cc (54.8 cu in)
Displacement R100:
980.7 cc (59.8 cu in)
Bore Stroke R80:
82 mm x 75.6 mm (3.23 in x 2.98 in)
Bore Stroke R90:
90 mm x 70.4 mm (3.54 in x 2.77 in)
Bore Stroke R100:
94 mm x 70.4 mm (3.70 in x 2.77 in)
Compression Ratio:
Varies by specific model variant (e.g., R100RT, R100GS), typically around 8.5:1 to 9.5:1
Horsepower R80:
Approx. 50-55 hp @ 6200 rpm (model dependent)
Horsepower R100:
Approx. 60-70 hp @ 7000 rpm (model dependent)
Torque R100:
Approx. 70-75 Nm @ 5000 rpm (model dependent)
Carburetors:
Typically twin Bing Constant Velocity (CV) carburetors, e.g., Bing 32/40/42/45 depending on model and year
Fuel Type:
Unleaded gasoline, minimum 91 octane (RON+MON)/2
Ignition System:
Contact breaker points ignition or early electronic ignition systems (depending on specific model variant within R100 range)
Oil Capacity:
Approx. 3.0 - 3.5 liters (3.2 - 3.7 US qt) with filter change
Oil Grade:
API SG or higher, viscosity typically 20W-50 or 10W-40 depending on climate (refer to specific manual for exact recommendations)
Gearbox Type:
5-speed, constant mesh, sequential manual gearbox
Drive Type:
Shaft drive to rear wheel
Clutch Type:
Single dry plate diaphragm spring clutch (operates from the right side of the engine)
Gearbox Oil Grade:
SAE 75W/90 or SAE 80W gear oil (API GL-4/GL-5)
Gearbox Oil Capacity:
Approx. 0.75 - 1.0 liter (0.79 - 1.05 US qt)
Wheelbase:
Varies by model, typically around 1430 mm - 1510 mm (56.3 in - 59.4 in)
Dry Weight:
Varies significantly by model (e.g., R80G/S, R100GS, R100RT), generally between 190 kg - 230 kg (419 lbs - 507 lbs)
Gross Vehicle Weight Rating:
Not typically specified in detail for motorcycles, but payload capacity is a consideration
Crash Test Data:
N/A (Motorcycles not subjected to standardized automotive crash testing)
Braking System:
Dual disc front brakes (on most models), single disc rear brake (or drum on some earlier/smaller variants). Often with Brembo components.
Lighting:
Halogen headlight, taillight, brake light, turn signals
Infotainment System:
N/A (Basic motorcycle of the era, no integrated infotainment systems)
ABS:
Optional on some R100 models (e.g., R100RT), known as ABS II.
Fairings Windshields:
Available on touring models like R100RT, R100RS offering significant weather protection and aerodynamic efficiency.
Oil Change Interval:
Typically every 5,000 - 7,500 km (3,000 - 5,000 miles) or annually, whichever comes first.
Valve Adjustment Interval:
Every 10,000 - 15,000 km (6,000 - 9,000 miles), critical for smooth running.
Filter Replacement Interval:
Oil filter with every oil change. Air filter inspection at regular intervals, replacement as needed.
Final Drive Oil Change:
Every 10,000 - 15,000 km (6,000 - 9,000 miles)
Engine Oil Grade:
BMW Motorrad recommends specific viscosity grades based on ambient temperature, typically 20W-50 or 10W-40. Always consult the manual for the definitive recommendation.
Brake Fluid Type:
DOT 4 brake fluid
Common Wear Items:
Clutch wear, wear in the swingarm pivot bearings, fork seal leaks, starter motor brushes, exhaust header pipe leaks.
Electrical Quirks:
Intermittent issues with the sidestand switch, loose wiring connections, worn ignition coil leads.
Engine Tuning Points:
Carburetor synchronization and jetting can be sensitive; proper valve lash is critical for performance and longevity.
Oil Filter Part Number:
Refer to manual for specific part numbers (e.g., Mann-Filter ML75, Mahle OC5, K&N KN-155 are common aftermarket replacements that fit many Airheads)
Manufacturer:
Bayerische Motoren Werke AG (BMW)
Founding Era:
Founded in 1916, automotive production began in the 1920s, motorcycles since 1923
Airhead Lineage:
The R80, R90, and R100 series are part of BMW's long-running and highly regarded 'Airhead' boxer engine platform, characterized by its air-cooled cylinders protruding on either side of the frame.
R90 Introduction:
The R90/6 and R90S were introduced in the mid-1970s as sportier, more powerful alternatives to earlier models.
R80 Introduction:
The R80 series (e.g., R80/7, R80G/S) appeared in the late 1970s and early 1980s, offering a balance of performance and usability. The R80GS pioneered the dual-sport ADV segment.
R100 Introduction:
The R100 series, including the R100RS, R100RT, and R100GS, represented the top of the Airhead line with larger displacement engines, more power, and advanced features for their time.
Production Era:
The Airhead platform was produced from the early 1970s through the mid-1990s. The 1990 models represent a mature iteration of this design.
Manufacturing Location:
Berlin, Germany (BMW Motorrad factory)
Industry Acclaim:
BMW's Airhead series, including these models, is widely acclaimed for its durability, reliability, and unique character, making them highly sought-after by enthusiasts and collectors.
Durability Reputation:
Exceptional, known for longevity with proper maintenance and often capable of hundreds of thousands of kilometers.
European Emission Standards:
Met contemporary European emission standards for motorcycles of the late 1980s/early 1990s.
