BMW R90 1981 Full Service Repair Manual

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🏷️ Basic Information Identification Make: BMW Model: R90 Year: 1981 Product Type: Full Service Repair Manual 👋 Introduction Market Position Target Audience: BMW R90 owners, mechanics, restorers, enthusiasts Value Proposition:...

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Type: Motorcycle

Vendor:

Sku: 417317

Tags: 1981 BMW Cars Misc Motorcycle R90

Product variants

Description

🏷️ Basic Information

Identification

Make:

Model:

Year:

Product Type:

Full Service Repair Manual

👋 Introduction

Market Position

Target Audience:

BMW R90 owners, mechanics, restorers, enthusiasts

Value Proposition:

Enables owners to perform all necessary maintenance and repairs, reducing reliance on costly service centers and preserving vehicle value.

Competitive Analysis

Competitors:

Haynes, Clymer, or other unofficial repair manuals (often less detailed or accurate)

Key Features

Feature 1:

Comprehensive diagnostic information specific to the R90 model.

Feature 2:

Detailed exploded diagrams and step-by-step repair instructions.

Feature 3:

Crucial technical specifications and torque values.

Feature 4:

Wiring schematics for accurate electrical system troubleshooting.

📋 Manual Details

Coverage Areas

Primary Coverage:

BMW R90 (1981 Model Year)

Engine Coverage:

All R90 engine variants

Chassis Coverage:

Frame, suspension, wheels, brakes

Electrical Coverage:

Wiring diagrams, lighting, ignition, starting, charging systems

Bodywork Coverage:

Body panels, fairings, seat, fuel tank, trim

Maintenance Coverage:

Scheduled maintenance, fluid changes, adjustments

Repair Coverage:

Engine rebuild, transmission overhaul, brake system repair, electrical troubleshooting

Troubleshooting Coverage:

Diagnostic procedures, common issues and solutions

Page Count

Estimated Page Count:

Likely 300-500 pages (typical for comprehensive service manuals of this era)

Manual Type

Type:

Full Service and Repair Manual

Language

Language:

English

Format

Format:

Digital (likely PDF)

📖 Manual Coverage

Systems Covered

Engine Mechanical:

Disassembly, inspection, repair, reassembly of all engine components (cylinders, pistons, crankshaft, camshafts, valves, etc.)

Engine Management:

Carburetor tuning and rebuilding, ignition system timing and adjustment, spark plug selection and replacement

Transmission Drivetrain:

Gearbox operation, clutch service, final drive maintenance and repair

Brakes:

Front and rear brake system overhaul, hydraulic fluid service, pad and caliper inspection/replacement

Suspension Steering:

Front fork service and seal replacement, rear shock absorber maintenance, steering head bearing adjustment

Electrical System:

Detailed wiring diagrams, troubleshooting guides for lights, horn, starter, alternator, battery charging system

Fuel System:

Fuel tank inspection, fuel line maintenance, carburetor cleaning and adjustment

Exhaust System:

Exhaust pipe and muffler inspection and replacement

Cooling System:

N/A (Air-cooled engine)

Procedures Included

Routine Maintenance:

Oil change, filter replacement, chain adjustment, lubrication points

Engine Overhaul:

Complete engine teardown and rebuild procedures with specifications

Carburetor Rebuilding:

Step-by-step instructions for disassembling, cleaning, and reassembling carburetors

Brake System Service:

Bleeding brake lines, replacing brake pads and discs

Electrical Troubleshooting:

Fault finding for starting issues, charging system problems, lighting malfunctions

Wheel Wheel Alignment:

Spoke tension adjustment, wheel balancing, steering alignment checks

Suspension Adjustment:

Front fork oil level and damping adjustments, rear shock preload settings

Bodywork Repair:

Minor dent repair, panel alignment, trim piece replacement

Technical Depth

Depth:

Comprehensive (from basic maintenance to full engine rebuilds and diagnostics)

Diagnostic Coverage:

Detailed diagnostic procedures, troubleshooting flowcharts

Specification Detail:

Torque specifications, clearances, tolerances, fluid capacities, electrical resistance values

📊 Manual Specifications

File Format

File Type:

Searchable Text:

Yes (Assumed for high-quality digital manuals)

Printable:

Print Quality

Image Resolution:

High-resolution, clear diagrams and photographs

Binding Type

Binding:

N/A (Digital Product)

Paper Type

Paper Quality:

N/A (Digital Product)

⚙️ Engine Specifications

Primary Engine

Engine Type:

Air-cooled, horizontally opposed twin-cylinder boxer engine

Displacement:

897 cc (54.7 cubic inches)

Bore X Stroke:

90.0 mm x 70.6 mm (3.54 in x 2.78 in)

Compression Ratio:

Approximately 8.2:1 (subject to specific market variations)

Performance

Horsepower:

Approximately 60 hp (45 kW) at 6250 rpm (DIN)

Torque:

Approximately 76 Nm (56 lb-ft) at 4500 rpm (DIN)

Fuel System

Carburetors:

Dual Bing constant velocity carburetors (e.g., Bing 32/32/36 or similar, depending on specific R90 variant and market)

Fuel Type:

Unleaded gasoline (premium recommended, octane rating as per manual specifications)

Ignition System

Ignition Type:

Battery-coil ignition with breaker points and centrifugal advance

Lubrication

Oil Type:

SAE 20W-50 or 10W-40 motorcycle specific engine oil (refer to manual for exact specification and seasonal recommendations)

Oil Capacity:

Approximately 2.0 - 2.5 liters (2.1 - 2.6 US quarts) with filter change (refer to manual for precise capacity)

Engine Codes

Engine Designation:

R90 series (specific engine codes may exist, e.g., R90/6, R90S)

🔧 Transmission

Standard

Transmission Type:

5-speed manual gearbox

Optional

Optional Transmissions:

N/A (Standard fitment for R90)

Features

Clutch Type:

Single dry plate clutch, hydraulically operated

Drive Type:

Shaft drive to rear wheel

Fluid Specifications

Gearbox Oil Type:

SAE 80W-90 hypoid gear oil (refer to manual for exact specification)

Fluid Capacities

Gearbox Oil Capacity:

Approximately 0.5 liters (0.5 US quarts) (refer to manual for precise capacity)

📐 Dimensions

Exterior

Wheelbase:

Approximately 1465 mm (57.7 inches) (R90/6)

Length:

Approximately 2230 mm (87.8 inches) (R90/6)

Weights

Dry Weight:

Approximately 200-215 kg (441-474 lbs) (depending on specific R90 variant and equipment)

Gross Vehicle Weight Rating:

Refer to vehicle's compliance plate/manual

Wheels Tires

Front Tire Size:

3.50-18 (e.g., 100/90-18)

Rear Tire Size:

4.00-18 (e.g., 110/90-18 or 120/90-18)

Wheel Type:

Spoked wheels with either aluminum or chrome rims

Bolt Pattern:

N/A (Not applicable for motorcycle wheels)

🛡️ Safety Features

Ratings

Safety Ratings:

N/A (Motorcycle safety is not rated by typical automotive bodies like NHTSA/Euro NCAP)

Active Features

Braking System:

Dual disc front brakes (R90S typically), single disc front (R90/6), drum brake rear. Hydraulic actuation.

Passive Features

Lighting:

Halogen headlight, tail light, brake light, turn signals

Mirrors:

Dual rear-view mirrors

💡 Technology Features

Infotainment

Infotainment System:

N/A (This era of motorcycle predates modern infotainment systems.)

Driver Assistance

Advanced Assistance:

N/A (No electronic driver assistance features.)

Connectivity

Connectivity Features:

N/A (No connectivity features.)

Instrumentation

Instrument Cluster:

Analog speedometer, tachometer, voltmeter (on some models), indicator lights for oil pressure, high beam, turn signals, neutral.

🔧 Maintenance

Service Intervals

Oil Change Interval:

Every 5,000 km (3,000 miles) or annually (refer to manual for precise interval and oil drain plug washer replacement).

Major Service Interval:

Every 10,000-15,000 km (6,000-9,000 miles), including valve clearance adjustment, spark plug replacement, and carburetor synchronization.

Valve Clearance Adjustment:

Every 5,000 km (3,000 miles) or as specified in the manual (typically 0.15 mm for both intake and exhaust, cold).

Fluid Specifications

Brake Fluid Type:

DOT 3 or DOT 4 brake fluid (refer to manual for exact specification and flush interval).

Final Drive Oil Type:

SAE 80W-90 hypoid gear oil (same as gearbox, refer to manual).

Fluid Capacities

Final Drive Oil Capacity:

Approximately 0.2 liters (0.2 US quarts) (refer to manual for precise capacity)

Known Issues

Common Issue 1:

Leaking output shaft seals and transmission output seals due to age and seal degradation.

Common Issue 2:

Carburetor float bowl gaskets and O-rings can degrade, leading to fuel leaks or poor running.

Common Issue 3:

Wear in the transmission selector drum and lever mechanism can lead to sloppy shifting or difficulty finding neutral.

Common Issue 4:

Electrical connections and wiring can corrode over time, leading to intermittent issues with lights, ignition, or charging.

Common Issue 5:

Aging rubber components such as fuel lines, intake boots, and fork seals will require replacement.

Common Issue 6:

Starter motor brushes may wear out, leading to slow or no engine cranking.

📚 Vehicle History

Brand Heritage

Brand Origin:

Bayerische Motoren Werke AG (BMW), Germany

Motorcycle Heritage:

BMW has a long and distinguished history in motorcycle manufacturing, dating back to the early 20th century, renowned for engineering excellence and durability.

Model Evolution

R90 Development:

The R90 was part of BMW's airhead boxer motorcycle lineage, evolving from earlier models. The R90/6 and R90S were introduced in 1973 as powerful and sophisticated touring and sport-touring motorcycles.

R90 Variants:

Key variants include the R90/6 (standard touring model) and the R90S (sportier version with dual disc brakes, clip-on handlebars, and often different bodywork).

Production

Production Period:

1973-1976

Production Location:

Berlin-Spandau, Germany

Significance:

The R90 series was a significant motorcycle for BMW, demonstrating their capability in producing large-displacement, high-performance boxer twins that were also reliable for long-distance travel.

🏆 Awards & Recognition

Recognitions

Historical Recognition:

The BMW R90 series, particularly the R90S, was critically acclaimed in its time for its performance, handling, and build quality, often considered a benchmark in the sport-touring motorcycle segment.

Ratings

Customer Satisfaction:

Consistently high ratings among enthusiasts for reliability and enduring design. Revered for its character and capability.

Certifications

Manufacturing Standards:

Produced under BMW's stringent German engineering and manufacturing quality standards of the era.