🏷️ Basic Information

Make:

BMW

Manual Product Name:

BMW R51-2 R51-3 R67-2 R67-3 R68 Repair Manual

Vehicle Model Codes Covered:

👋 Introduction

Market Position:

Essential technical documentation for owners and enthusiasts of classic BMW motorcycles, catering to restoration, maintenance, and performance tuning.

Competitive Analysis:

This manual provides a singular source of detailed German technical information, crucial for accurate maintenance and repair of these specific BMW models, often scarce in English-language resources for this era.

Key Features:

Part Diagrams Usefulness:

High-quality part diagrams are critical for identifying specific components during disassembly and ordering replacements, ensuring accuracy and reducing errors.

📋 Manual Details

Manual Coverage Description:

Complete service manual covering tear down and rebuild, pictures, part diagrams, torque specifications, maintenance, and troubleshooting.

Page Count:

126

Manual Type:

Workshop/Service/Repair Manual

Language:

German

Format:

Digital PDF

📖 Manual Coverage

Systems Covered:

Carburetor Details:

Specific carburetor models (e.g., Bing 24/26/28) used on these bikes, including jet sizes, float bowl adjustment, and idle speed settings.

Procedures Included:

Timing Adjustment:

Detailed procedures for setting ignition timing using a feeler gauge or timing light (if applicable).

Technical Depth:

Comprehensive: From basic maintenance to complete engine and gearbox rebuilds, suitable for both amateur mechanics and professional technicians.

Special Tools:

The manual may indicate specific BMW special tools required for certain procedures, such as flywheel removal or valve seat lapping.

📊 Manual Specifications

File Format Details:

Adobe PDF, digital download, printable pages.

Searchability:

Digital PDF format typically allows for keyword searching of technical terms, greatly aiding in efficient information retrieval.

Print Quality Description:

High-resolution digital format with clear images and diagrams, suitable for printing.

Binding Type:

N/A (Digital PDF - Printable)

Paper Type:

N/A (Digital PDF - Printable)

⚙️ Engine Specifications

Engine Type General:

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

Performance Details:

Specific horsepower and torque figures vary by model (R51/2, R51/3, R67/2, R67/3, R68). The manual will detail these for each variant, including optimal tuning parameters. R68 is known for its higher performance output in this range.

Fuel System Details:

Typically equipped with Bing or other period-appropriate carburetors. The manual covers carburetor identification, adjustment, cleaning, and rebuilding.

Engine Displacement Models:

{'R51/2': '494 cc', 'R51/3': '494 cc', 'R67/2': '594 cc', 'R67/3': '594 cc', 'R68': '594 cc'}

Engine Bore Stroke Details:

Specific bore and stroke dimensions for each engine variant will be detailed in the manual for accurate engine building and part selection.

Compression Ratio Models:

The manual will provide correct compression ratios for each model, essential for diagnosing engine health and tuning.

Valve Train Description:

Overhead valve (OHV) configuration with pushrods operating the valves. The manual covers valve clearance adjustment procedures.

Ignition System Details:

Distributor-based ignition system with contact breakers. The manual details timing specifications, contact breaker gap adjustment, and troubleshooting.

🔧 Transmission

Transmission Type:

4-speed manual gearbox

Transmission Features:

Foot-shift operation, with some models potentially having options for specific shift mechanisms. The manual will cover clutch operation and adjustment.

Transmission Fluid Specifications:

The manual will specify the correct type and viscosity of gear oil for the transmission, likely a GL-4 rated oil.

Gear Ratios:

The manual will include specific gear ratios for all four forward gears and potentially reverse (if applicable to certain export versions or modifications), critical for performance tuning.

Clutch Type:

Single dry plate clutch.

Final Drive Type:

Shaft drive with enclosed universal joint and bevel gear final drive.

📐 Dimensions

Exterior Dimensions General:

Specific dimensions (length, width, height) and wheelbase will be detailed for each model covered. These motorcycles are characterized by their classic roadster styling.

Wheelbase:

Specific wheelbase figures for each model will be detailed in the manual, influencing handling characteristics.

Weight Specifications:

Dry weight and curb weight for each model will be provided, crucial for handling and transport.

Gross Vehicle Weight Rating:

While not typically published as GVWR for motorcycles of this era, the manual may provide load capacity recommendations.

Weight Distribution:

The manual's technical details on chassis and component placement implicitly cover weight distribution considerations for optimal handling.

Wheel Type:

Spoked wheels with aluminum or steel rims.

Tire Size Recommendations:

The manual will specify recommended tire sizes and pressures for front and rear wheels for optimal performance and safety.

Wheel Bolt Pattern:

N/A (typical motorcycle wheel attachment is via axle nut).

🛡️ Safety Features

Safety Ratings:

N/A for this era of motorcycle; safety is addressed through proper maintenance and operational procedures outlined in the manual.

Active Safety Features:

Braking System Type:

Drum brakes (front and rear). The manual details brake shoe inspection, adjustment, and replacement procedures.

Passive Safety Features:

💡 Technology Features

Infotainment Systems:

N/A (Classic motorcycles predating modern infotainment systems).

Driver Assistance Features:

N/A (Classic motorcycles).

Connectivity Features:

N/A (Classic motorcycles).

🔧 Maintenance

Service Intervals General:

The manual will detail specific mileage-based service intervals for engine oil changes, gearbox oil, final drive oil, spark plug replacement, valve adjustments, and lubrication points.

Lubrication Schedule:

Detailed schedule for greasing specific points, such as wheel bearings, steering head bearings, and suspension linkages.

Fluid Specifications:

Oil Capacity Engine:

The manual will provide the exact engine oil capacity for each model, crucial for correct filling.

Oil Capacity Gearbox:

The manual will provide the exact gearbox oil capacity for each model.

Oil Capacity Final Drive:

The manual will provide the exact final drive oil capacity for each model.

Common Issues And Solutions:

The manual will address potential wear items such as crankshaft seals, gearbox synchromesh (if applicable), carburetor tuning consistency, and ignition timing drift. It will provide diagnostic steps and repair procedures for these.

Electrical System Common Issues:

The manual will cover potential issues with generator output, battery charging, and the reliability of the lighting system, offering diagnostic methods.

Fuel Tank And Lines:

The manual will cover inspection and maintenance of the fuel tank for corrosion, and fuel lines for degradation or blockage.

📚 Vehicle History

Brand Heritage:

BMW Motorrad, renowned for its engineering prowess and robust motorcycles, particularly its iconic boxer-twin engine configurations.

Brand Philosophy:

Emphasis on engineering quality, durability, and performance, which is reflected in the design and construction of these motorcycles.

Model Evolution Summary:

These models represent key steps in BMW's post-war motorcycle development, building upon the success of earlier boxer twins and introducing refinements in performance and reliability. The R51/2 and R51/3 are predecessors to the R67 series, with the R68 being a more performance-oriented model of its era.

Design Philosophy:

The boxer-twin engine mounted longitudinally in the frame provides excellent weight distribution and accessibility for maintenance, a hallmark of BMW motorcycle design.

Performance Differences:

The R68, in particular, was positioned as a sportier offering with a higher compression ratio and increased power output compared to the more touring-oriented R67 models.

Production Period:

The models covered span from the late 1940s through the mid-1950s (e.g., R51/2 approx. 1950-1951, R51/3 approx. 1951-1954, R67/2 approx. 1951-1954, R67/3 approx. 1951-1956, R68 approx. 1952-1954).