Model Years Covered:
1940, 1941, 1942, 1943, 1944, 1945, 1946, 1947
Oem Manual Code:
Likely an internal Harley-Davidson service bulletin or manual series for this era, specific code not provided in product info but representative of factory documentation.
Historical Significance:
These Harley-Davidson Big Twins represent a crucial era of American motorcycle manufacturing, known for their robust engineering and iconic design.
Market Niche:
The manual targets owners and restorers of vintage Harley-Davidson motorcycles, a passionate segment of the classic vehicle market.
Resource Value:
Essential for maintaining, repairing, or restoring these historically significant machines, ensuring authenticity and proper function.
Engine:
Detailed coverage of Harley-Davidson Big Twin engines, including disassembly, assembly, tuning, and troubleshooting.
Transmission:
Comprehensive instructions for the transmission system, including maintenance, repair, and adjustment.
Electrical System:
In-depth coverage of the electrical system, including wiring diagrams, ignition, lighting, and charging systems.
Fuel System:
Detailed information on the fuel delivery system, including carburetor maintenance, fuel lines, and filters.
Braking System:
Service procedures for the braking system, including maintenance and adjustments.
Suspension And Steering:
Guidance on the front fork, rear suspension, and steering mechanisms.
Chassis And Frame:
Information related to the motorcycle's frame, including inspections and repairs.
Bodywork And Trim:
Details on the fenders, tanks, and other body components.
Maintenance:
Routine maintenance tasks, including oil changes, filter replacements, and lubrication schedules.
Troubleshooting:
Diagnostic procedures and solutions for common problems encountered with these models.
Repair:
Step-by-step instructions for engine rebuilds, transmission overhauls, and other major repair tasks.
Adjustment:
Procedures for adjusting clutch, brakes, ignition timing, and carburetor settings.
Inspection:
Guidelines for inspecting critical components for wear and damage.
Depth Level:
Comprehensive factory-level detail, suitable for both experienced mechanics and dedicated enthusiasts.
Diagnostic Capabilities:
Detailed diagnostic flowcharts and symptom-based troubleshooting guides.
Rebuild Information:
Full engine and transmission rebuild specifications, including torque values and clearances.
Searchability:
Likely text-searchable if the PDF was created from an OCR'd document or original digital source.
Printability:
Designed for printing, allowing users to create physical copies of specific sections or the entire manual.
Binding Recommendation:
Ideal for spiral binding or comb binding for ease of use in a workshop environment.
Paper Recommendation:
Recommended for printing on durable, grease-resistant paper suitable for workshop conditions.
Engine Type:
Air-cooled, V-twin, overhead valve (OHV) OHV
Displacement Range:
Typically 74 cubic inches (1200cc) and 80 cubic inches (1310cc) for Big Twin models of this era.
Bore X Stroke:
Varies by specific displacement, e.g., 74ci: 3.4375 in. x 4.00 in. (87.3mm x 101.6mm); 80ci: 3.4375 in. x 4.3125 in. (87.3mm x 109.5mm)
Horsepower Estimate:
Approximately 25-35 HP (varies by engine size and tuning).
Torque Estimate:
Significantly geared for low-end torque, characteristic of classic V-twins.
Carburetor Type:
Typically Linkert carburetors or early equivalents. Manual will cover specific models and settings.
Fuel Octane Rating:
Requires leaded gasoline of appropriate octane for the era. Manual will specify.
Transmission Type:
3-speed or 4-speed manual transmission, foot-clutch, hand-shift operation was common.
Gear Ratios:
Specific gear ratios will be detailed in the manual for each transmission variant.
Clutch Type:
Typically a dry plate clutch, operated by a foot pedal.
Shift Mechanism:
Hand-operated shift lever on the right side of the tank or frame.
Infotainment Features:
None, as these are pre-electronic era motorcycles. Focus is on mechanical function and rider control.
Driver Assistance Features:
None. Technology is entirely mechanical and rider-controlled.
Connectivity Features:
None. Purely mechanical operation.
Oil Change Interval:
Typically recommended every 1000-2000 miles or annually, depending on usage. Manual provides specific guidance.
Ignition Timing Check:
Regular checks and adjustments for optimal performance and engine health.
Engine Oil Type:
Primarily SAE 50 or SAE 60 straight-weight mineral oil (non-detergent recommended for older engines). Specific viscosity and quantity in manual.
Transmission Oil Type:
Gear oil suitable for heavy-duty transmissions, likely SAE 90 or SAE 140. Manual specifies exact type and capacity.
Primary Chaincase Oil Type:
Motor oil (same as engine oil or specified equivalent) is often used in the primary chaincase. Manual will detail.
Carburetor Tuning:
Linkert carburetors can be finicky and require precise adjustment. Manual provides tuning procedures.
Oil Leaks:
Common in vintage motorcycles due to aging seals and gaskets. Manual guides on seal replacement and gasket maintenance.
Ignition System Maintenance:
Points and condenser require regular cleaning and adjustment. Manual covers ignition system troubleshooting.
Valve Adjustment:
Periodic valve lash adjustments are crucial for engine performance. Manual details the correct procedure.
Harley Davidson Legacy:
Harley-Davidson has a long-standing reputation for building powerful, American-made motorcycles, particularly their V-twin engines.
Big Twin Development:
The Big Twin line evolved from earlier Flathead models, introducing the OHV Knucklehead and Panhead designs during this period, characterized by their distinctive valve cover shapes.
Production Period Context:
This period includes World War II, during which Harley-Davidson also produced motorcycles for military use, influencing design and manufacturing processes.
Historical Recognition:
Harley-Davidson Big Twins from this era are highly sought after by collectors and are recognized as icons of American industrial design and automotive history.
Restoration Quality:
The manual is critical for achieving concours-level restorations due to its comprehensive and accurate information.
Factory Certification:
As an official factory service manual, it provides the definitive procedures and specifications for these vehicles.
