Market Position:
This manual serves the crucial need for repair and maintenance information for iconic BMW 'Airhead' motorcycles, a segment with a dedicated enthusiast base.
Competitive Analysis:
Directly competes with other aftermarket service manuals for vintage BMW motorcycles. Its value lies in its specificity to the 1978 models and the R80, R90, R100 range.
Key Features:
Authoritative, factory-level repair guidance for essential maintenance and complex repairs, essential for preserving the longevity and performance of these classic machines.
Systems Covered Overview:
Comprehensive coverage of all mechanical, electrical, and chassis systems for the specified BMW R series models.
Page Count:
Estimated 300-400 pages (typical for this era and scope)
Manual Type:
Service Repair Workshop Manual
Format:
Likely printed publication, potential for scanned PDF.
Engine Systems:
Engine assembly, disassembly, tuning, lubrication, cooling, fuel delivery (carburetor specifics), ignition system (points, coils, timing), exhaust system.
Transmission Drivetrain:
Gearbox (5-speed), clutch operation and adjustment, driveshaft, final drive assembly and lubrication.
Chassis Suspension:
Frame inspection and repair, front fork (telescopic, oil type, seals), rear shock absorbers (spring preload, damping adjustment), wheel bearings, steering head bearings.
Braking System:
Front and rear brake systems (drum and disc where applicable), brake fluid specifications, bleeding procedures, caliper/master cylinder overhaul.
Electrical System:
Wiring diagrams, battery maintenance, charging system (alternator/generator), lighting system (headlight, taillight, indicators), starter motor, horn, instrument cluster.
Fuel System:
Fuel tank, fuel lines, carburetor types (Bing CV), fuel filter replacement, idle speed and mixture adjustment.
Maintenance Procedures:
Scheduled maintenance, oil changes, filter replacements (oil, fuel, air), spark plug replacement, valve clearance adjustment, lubrication points.
Repair Procedures:
Engine rebuilds, gearbox overhauls, carburetor tuning, electrical component repair, suspension component replacement, brake system repairs.
Troubleshooting:
Diagnostic charts for common performance issues, starting problems, electrical faults, and mechanical noises.
Technical Depth:
Detailed, step-by-step instructions with torque specifications, clearances, and diagnostic values suitable for professional mechanics and experienced DIY enthusiasts.
File Format:
If digital, typically PDF. High-resolution scans are preferred for clarity of diagrams.
Print Quality:
Professional printing with clear, legible text and high-contrast diagrams. For digital, clear, searchable PDFs are essential.
Binding Type:
If printed, typically a durable comb binding or saddle-stitched booklet for easy page turning and lay-flat functionality.
Paper Type:
If printed, semi-gloss or matte finish paper that resists smudging and grease.
Engine Type:
Air-cooled, four-stroke boxer twin-cylinder engine.
Displacement R80:
797.5 cc
Displacement R90:
897.9 cc
Displacement R100:
979.7 cc
Horsepower R80 Approx:
50 HP @ 6200 RPM
Horsepower R90 Approx:
60 HP @ 6800 RPM
Horsepower R100 Approx:
65 HP @ 6500 RPM
Torque R80 Approx:
60 Nm (44 lb-ft) @ 4500 RPM
Torque R90 Approx:
70 Nm (52 lb-ft) @ 5000 RPM
Torque R100 Approx:
74 Nm (55 lb-ft) @ 5000 RPM
Carburetor Type:
Typically dual Bing 32mm or 40mm Constant Velocity (CV) carburetors depending on model variant.
Fuel Type:
Unleaded gasoline (91 RON / 87 AKI or higher recommended).
Safety Ratings Era:
Motorcycles of this era did not undergo standardized crash testing as with modern cars. Safety features primarily relate to braking and handling.
Active Safety Features:
Responsive braking system (disc front, drum/disc rear depending on model), stable chassis and suspension, effective lighting.
Passive Safety Features:
Robust frame construction, rider skill is the primary passive safety measure.
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 km (6,000 miles).
Spark Plug Replacement:
Every 10,000 km (6,000 miles).
Engine Oil Type:
SAE 20W-50 or SAE 10W-40 API SG/SH (check manual for exact specification). Capacity: approx. 2.5 Liters (with filter change).
Transmission Oil Type:
Hypoid gear oil SAE 90 API GL-5 (check manual). Capacity: approx. 0.25 Liters.
Final Drive Oil Type:
Hypoid gear oil SAE 90 API GL-5 (check manual). Capacity: approx. 0.25 Liters.
Fork Oil Type:
Telescopic fork oil (e.g., Motul Fork Oil Expert 10W or equivalent). Capacity: approx. 185-225 ml per fork leg, depending on model.
Brake Fluid Type:
DOT 3 or DOT 4 brake fluid (check manual).
Known Issues Common:
Carburetor synchronization and tuning, electrical connector corrosion, output shaft seal leaks, starter motor brushes wear, fork seal leaks, clutch cable adjustment.
Brand Heritage:
BMW has a long and storied history in motorcycle manufacturing, dating back to 1923. The boxer-twin engine configuration is a signature element, known for its reliability and torque.
Model Evolution:
The 1978 models represent a significant evolution of the /5 series, incorporating updates to engines, chassis, and styling. The R100S introduced sportier elements and higher performance.
Production Period:
The /7 series, including these models, was produced from the mid-1970s into the early 1980s, making the 1978 model a key year in this lineage.
Recognitions:
While these specific models may not have formal 'awards' in the modern sense, they are widely recognized and celebrated within the motorcycle community for their durability, engineering, and classic styling.
User Ratings:
Consistently receive high ratings from owners for reliability, ride quality, and the unique character of the boxer engine and shaft drive.
Certifications:
Not applicable in the context of consumer certifications.
