🏷️ Basic Information Identification Make: Harley-Davidson Model: Big Twin (Knucklehead & Flathead) Model Designations: EL, FL, U, UL, ULH, WL (1940-1947 era variations) Production Years Covered By Manual: 1940, 1941, 1942, 1943, 1944, 1945, 1946, 1947 Historical Production Years Extended Coverage: 1937 onwards for Big Twin models 👋 Introduction Market Position Target Audience: Harley-Davidson owners and mechanics specializing in vintage Big Twin models Competitive Analysis Value Proposition: Provides essential, detailed technical data for maintaining and repairing iconic pre-unit Harley-Davidson motorcycles Key Features Manual Strengths: Detailed procedures, exploded views, diagrams, illustrations, troubleshooting chart, comprehensive coverage 📋 Manual Details Coverage Areas Manual Type: Workshop Service Repair Manual Language: English Page Count Total Pages: 166 Format File Format: PDF Compatibility: All Versions of Windows & Mac Print Quality Printable: Yes, without restriction Delivery Method Delivery: Download link upon payment completion Requirements Software Requirements: Adobe PDF Reader 📖 Manual Coverage Systems Covered Engine Systems: Engine Overhaul, Engine Lubrication, Carburetor Servicing Electrical System: Full coverage of the electrical system Drivetrain Systems: Transmission servicing Chassis Systems: Wheels & Hubs, Fork, Frame & Handlebar assembly Ancillary Systems: Sidecar mounting and servicing Cooling System: Air-cooled engine systems Exhaust System: Implied coverage in engine overhaul and tuning Procedures Included Maintenance Procedures: Initial Servicing of New Motorcycle, Regular Maintenance Repair Procedures: Detailed repair procedures for all covered systems Troubleshooting: Trouble Chart for diagnostics Assembly Procedures: Step-by-step instructions for disassembly and re-assembly of all major components. Technical Depth Depth Of Information: Comprehensive technical information for all repairs, making service simple Diagnostic Tools: Implicitly covers use of standard mechanic's tools and understanding of mechanical principles Visual Aids: Exploded views, diagrams, and illustrations for easy identification, disassembly, and re-assembly Special Tools: Likely details required special tools for specific procedures. Specifications Tables: Contains essential specifications, settings, and tolerances for accurate repairs and adjustments. 📊 Manual Specifications File Attributes File Type: Digital (PDF) Print Quality Page Quality: Printable pages, assumed to be of good resolution for clarity Binding Type Binding: Not Applicable (Digital Download) Paper Type Paper: Not Applicable (Digital Download) ⚙️ Engine Specifications Primary Engine Engine Type: V-Twin Engine Configurations Covered: Overhead Valve (O.H.V.) Knucklehead and Side Valve (Flathead) engines Displacement Covered O H V Displacement: 61 Cu. In. (1000 c.c.) and 74 Cu. In. (1200 c.c.) Flathead Displacement: 74 Cu. In. (1200 c.c.) and 80 Cu. In. (1300 c.c.) Performance Horsepower And Torque: Specifications and adjustment procedures for achieving optimal performance will be detailed within the manual. Compression Ratio: Specifications for standard and potentially high-compression variants. Fuel System Carburetor Servicing: Detailed procedures for servicing carburetors (likely including Stromberg or Linkert models specific to the era). Lubrication System Engine Lubrication: Comprehensive information on lubrication systems, oil types, capacities, and maintenance. Engine Construction Cylinder Head Design: Overhead Valve (Knucklehead) and Side Valve (Flathead) Ignition System Ignition Type: Battery and Coil ignition system (or Magneto for some variations, though less common in these years for Big Twins) 🔧 Transmission Standard Transmission Type: 4-speed constant mesh manual transmission Features Transmission Servicing: Detailed information on transmission overhaul, adjustment, and maintenance. 📐 Dimensions Exterior Frame Type: Duplex cradle frame Weights Dry Weight: Varies by model, typically around 500-600 lbs (227-272 kg) Gross Vehicle Weight Rating: Not specified, but implies capacity for rider, passenger, and moderate load. 💡 Technology Features Infotainment Infotainment Systems: N/A (Vintage motorcycle technology focuses on mechanical and electrical systems, not infotainment in the modern sense). Driver Assistance Driver Assistance Features: N/A (Vintage motorcycle technology). Connectivity Connectivity Features: N/A (Vintage motorcycle technology). 🔧 Maintenance Service Intervals Initial Service: Specific guidance on initial servicing of new motorcycles is included. Fluid Specifications Engine Oil Type: Manual will specify appropriate oil types (e.g., mineral oils, potentially SAE 50 or 60 depending on ambient temperature and specific model). Transmission Oil Type: Manual will specify appropriate transmission lubricant (e.g., Harley-Davidson's original specifications or equivalent). Primary Chain Case Oil: Likely includes specifications for primary chain case lubrication. Known Issues Common Wear Items: Covers maintenance for areas prone to wear such as valve guides, cam followers, primary drive chain, and wheel bearings. Carburetor Tuning: Procedures for tuning and troubleshooting common carburetor issues like rough idling or poor acceleration. Oil Leaks: Procedures for sealing and preventing common oil leaks associated with vintage V-twins. Adjustments Ignition Timing: Detailed procedures for setting and checking ignition timing are expected. Clutch Adjustment: Guidance on clutch adjustment for proper operation. Brake Adjustment: Procedures for adjusting drum brakes which were standard on these models. 📚 Vehicle History Brand Heritage Harley Davidson Legacy: Harley-Davidson's Big Twins from this era represent a pivotal period in American motorcycle manufacturing, known for their robust construction and iconic styling. Model Evolution Knucklehead Era: The Knucklehead (introduced 1936) was Harley-Davidson's first mass-produced OHV engine, revolutionary for its time with features like positive valve oiling and enclosed valve train. Flathead Era: The Flathead (Side Valve) engine was a...