🏷️ Basic Information

Make:

BMW

Model:

R90

Model Designation:

R90/6

Model Notes:

This manual primarily covers the R90/6 model, although BMW often used the R90 designation broadly for related models.

Chassis Code:

247

Engine Code:

247

👋 Introduction

Category:

Premium Motorcycle Segment

Target Audience:

Enthusiasts, owners, and independent mechanics seeking detailed repair and maintenance information for classic BMW motorcycles.

Key Competitors:

Moto Guzzi V-twin models, Ducati V-twin models, other large-displacement European and Japanese motorcycles of the era.

Distinctive Elements:

Shaft drive, boxer twin engine, robust build quality, touring capability, classic styling.

Manual Value Proposition:

Provides essential, in-depth knowledge for preserving and maintaining a significant piece of BMW motorcycle history, empowering owners with the ability to perform complex tasks.

📋 Manual Details

Years Covered:

1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996

Model Variants Covered:

All R90 variants, primarily R90/6, potentially including closely related R90S model specifics if shared by design.

Estimated Pages:

Over 300 pages (typical for comprehensive service manuals of this era)

Type:

Service and Repair Manual

Language:

English

Format:

Downloadable PDF

📖 Manual Coverage

Engine:

Complete engine overhaul, tuning, component diagnosis (e.g., cylinders, pistons, crankshaft, camshaft, valve train, timing chain, oil pump).

Fuel System:

Carburetor service (e.g., Bing CV), fuel pump, fuel lines, fuel tank, fuel filter replacement.

Transmission:

Gearbox disassembly, assembly, inspection, lubrication, clutch service (dry clutch for R90S, wet clutch for R90/6), drive shaft, final drive.

Electrical System:

Ignition system (breaker points, coils, spark plugs), lighting, charging system (alternator, voltage regulator), starter motor, battery, wiring diagrams, switches, fuses.

Brakes:

Front and rear brake systems (dual front discs for R90/6, single disc for R90S), master cylinder, brake lines, calipers, brake pad replacement, brake fluid service.

Suspension And Steering:

Front fork (conventional telescopic) overhaul, rear shock absorber replacement, swingarm bearings, steering head bearings, wheel bearings.

Chassis And Bodywork:

Frame inspection, seat, fuel tank removal/installation, fenders, exhaust system, side stand, center stand.

Maintenance:

Routine checks, oil changes, filter replacements, spark plug tuning, valve clearance adjustment, brake bleeding, lubrication points.

Troubleshooting:

Diagnostic charts for common problems, identifying causes of poor performance, starting issues, electrical faults.

Repair:

Step-by-step instructions for component replacement, major overhauls, and system repairs.

Technical Specifications:

Torque values, clearances, fluid capacities, electrical resistance values, ignition timing settings.

Depth:

Comprehensive: Covers everything from basic owner maintenance to full engine and transmission rebuilds, electrical system diagnostics, and chassis overhauls.

📊 Manual Specifications

File Type:

PDF

Searchability:

Likely text-searchable (depending on original scan quality)

Resolution:

Variable, but assumed to be clear enough for technical information display and printing.

Type:

N/A (Downloadable Digital Format)

Type:

N/A (Digital Format)

⚙️ Engine Specifications

Type:

Air-cooled, four-stroke, horizontally opposed twin-cylinder boxer engine

Displacement:

900 cc (actual displacement for R90/6 is 897 cc)

Bore X Stroke:

90 mm x 70.6 mm

Compression Ratio:

8.2:1 (R90/6)

Horsepower:

60 hp (44 kW) at 6500 rpm (R90/6)

Torque:

75 Nm (55 lb-ft) at 5500 rpm (R90/6)

Carburetors:

2 x Bing 32/32 mm CV (Constant Velocity) carburetors (R90/6)

Fuel Type:

Unleaded premium gasoline

Oil Capacity:

Approx. 3.0 liters (including filter)

Oil Filter Type:

Spin-on cartridge (e.g., Mann-Filter W 712/3 or equivalent)

🔧 Transmission

Type:

5-speed manual gearbox

Drive:

Shaft drive to rear wheel

Clutch Type:

Single dry plate clutch (R90S), Single wet multi-plate clutch (R90/6)

Final Drive Ratio:

Typically 32/11 or 33/11 depending on model variant and intended use.

Transmission Oil Capacity:

Approx. 1.3 liters

Transmission Oil Spec:

SAE 75W/90 API GL-5 gear oil

📐 Dimensions

Length:

Approx. 2180 mm (R90/6)

Width:

Approx. 750 mm (handlebar width)

Height:

Approx. 1170 mm (seat height)

Dry Weight:

Approx. 200 kg (R90/6)

Gross Vehicle Weight:

Approx. 400 kg

Fuel Tank Capacity:

24 liters (including 3.5-liter reserve)

🛡️ Safety Features

Crash Test Data:

N/A (Motorcycle safety ratings were not standardized in the same way as cars during this era.)

Braking System:

Dual front disc brakes (R90/6), single rear disc brake. Effective stopping power for the era.

Frame Design:

Steel tube duplex cradle frame providing rigidity and stability.

Lighting:

Halogen headlamp, taillight, turn signals.

💡 Technology Features

System Type:

N/A (Focus on mechanical and electrical systems for this era of motorcycle. No integrated infotainment).

🔧 Maintenance

Oil Change Interval:

Every 5,000 km or annually, whichever comes first.

Valve Clearance Check:

Every 10,000 km or as specified in the manual.

Spark Plug Replacement:

Every 10,000 - 15,000 km, or based on condition.

Brake Fluid Flush:

Every 2 years.

Engine Oil Spec:

SAE 20W/50 or 10W/40 API SG or higher (check manual for specific recommendations based on climate).

Brake Fluid Spec:

DOT 4

Common Wear Items:

Clutch wear, steering head bearings, wheel bearings, swingarm bearings, exhaust pipe corrosion, aging electrical wiring insulation.

Engine Specific Concerns:

Potential for oil leaks at base gasket and pushrod tubes, valve guide wear on high-mileage engines, timing chain tensioner wear.

Carburetor Issues:

Difficulty in maintaining synchronization, wear in throttle slides or needle jets.

📚 Vehicle History

Bmw Motorcycle Legacy:

BMW has a long history of producing robust, reliable, and technologically advanced motorcycles, particularly known for their boxer twin engines and shaft drive.

R90 Series Introduction:

The R90 series (R90/6 and R90S) were introduced in 1973 as a more powerful and refined iteration of BMW's boxer twin platform, succeeding models like the R75/5.

R90 Development:

The R90/6 featured a 60 hp engine for broader appeal, while the R90S (with 67 hp, sportier styling, and dual front discs) was the flagship model. The production run spanned a significant period, reflecting its popularity and adaptability.

Manufacturing Location:

Berlin-Spandau, Germany

Production Years:

1973-1976 for the R90/6 and R90S. The manual's extended coverage into 1996 suggests it may also include information applicable to later models that retained similar core architecture or maintenance procedures, or it is a broad compilation of service data.

🏆 Awards & Recognition

Contemporary Reviews:

Critically acclaimed for performance, handling, comfort, and build quality in period reviews. Often praised for its touring capabilities and character.

Owner Satisfaction:

High enduring owner satisfaction due to reliability and classic appeal, making it a sought-after model.

Certification Type:

N/A (Not applicable to aftermarket repair manuals).