🏷️ Basic Information Identification Make: Harley-Davidson Model: EL "Knucklehead" Model Nickname: Knucklehead Product Type: Workshop Service Repair Manual Codes Engine Family Code: U 👋 Introduction Market Position Target Audience: Do-it-yourself enthusiasts and experienced mechanics working on Harley-Davidson Knucklehead motorcycles from 1940-1947. Key Features Instruction Format: Step-by-step instructions with numbered procedures and bold figure numbers for easy reference to illustrations. Visual Aid Quality: Detailed illustrations, drawings, and photos to guide users through procedures. Information Accessibility: Numbered table of contents for quick navigation; printable pages for workshop use. 📋 Manual Details Coverage Areas Vehicle Years: 1940, 1941, 1942, 1943, 1944, 1945, 1946, 1947 Page Count Estimated Page Count: Comprehensive (exact number not specified, but implied extensive) Manual Type Type: Factory Service Repair Manual Language Language: English Format File Format: PDF 📖 Manual Coverage Systems Covered Engine Mechanical: Full coverage including disassembly, inspection, repair, and reassembly of all engine components. Engine Electrical: Includes ignition system, lighting, charging system, and wiring schematics. Emission Control: Details on any applicable emission control systems for the period, though likely minimal for these years. Fuel System: Coverage of fuel tanks, fuel lines, carburetors, and fuel delivery systems. Suspension System: Front fork (Girdraulic or Springer, depending on specific model year) and rear suspension components. Clutch System: Complete service and repair procedures for the clutch assembly. Transmission System: Manual transaxle (gearbox) disassembly, repair, and reassembly. Driveshaft And Axle: Details on the final drive mechanism (chain drive). Steering System: Handlebar controls, steering head bearings, and front end geometry. Brake System: Front and rear brake mechanisms (typically drum brakes for this era). Body Interior Exterior: Bodywork, fenders, fuel tanks, seating, and trim components. Body Electrical System: Wiring diagrams for lights, horn, and other electrical accessories. Restraint Systems: While not applicable in the modern sense, this might refer to any securing mechanisms for components or accessories. Procedures Included Maintenance: Routine servicing, lubrication, adjustments, and inspections. Troubleshooting: Diagnostic procedures for identifying and resolving common mechanical and electrical issues. Repair: Detailed step-by-step instructions for component repair and replacement. Rebuilds: Comprehensive guidance for complete engine and transmission rebuilds. Electrical Diagnostics: In-depth troubleshooting of electrical circuits using provided wiring diagrams. Technical Depth Depth: Complete workshop level, suitable for both DIY enthusiasts and experienced mechanics. Detail Level: Detailed illustrations, diagrams, wiring schematics, and specifications are included. 📊 Manual Specifications File Format File Format: PDF Print Quality Printability: Fully printable pages Zoom Capability: Zoom IN/OUT supported Binding Type Binding: Digital (PDF) Paper Type Paper Type: N/A (Digital Format) Delivery Delivery Method: Instant Download Requirements Software Requirements: Adobe PDF Reader & WinZip Compatibility Operating Systems: All Versions of Windows & Mac ⚙️ Engine Specifications Primary Engine Engine Type: V-twin, air-cooled, OHV (Overhead Valve) Displacement: 61 cubic inches (1000cc) - EL model; 74 cubic inches (1200cc) - FL model (though this manual specifically references the EL designation which typically refers to the 61ci). Bore X Stroke: 3.3125 in x 3.5 in (approximate, varies slightly by year/specific sub-model) Performance Horsepower: Approximately 30-35 HP (exact figures vary based on tuning and specific model year) Torque: Not typically published in easily accessible historical figures, but known for strong low-end grunt. Fuel System Carburetion: Single Linkert carburetor (specific model varies, e.g., M-series) Fuel Type: Gasoline Lubrication System Oil Type: Motor oil (e.g., SAE 50 or SAE 20W-50, depending on climate and specific recommendations, often a straight-weight oil was used). Manual will specify. Oil Capacity: Approximately 3-4 US quarts (manual will specify exact capacity and check procedure). 🔧 Transmission Standard Type: 4-speed manual constant mesh gearbox Optional Type: N/A (4-speed manual was standard for this period) Features Engagement Method: Foot-operated clutch lever and hand-operated shifter (typically right-hand side for up/down shifting). Fluid Type Fluid Specification: Gear oil (specific grade will be detailed in the manual, e.g., SAE 80W-90 or similar gear lubricant). 📐 Dimensions Exterior Wheelbase: Approximately 56.5 inches (varies slightly by year) Weights Dry Weight: Approximately 485-525 lbs (varies by specific model and equipment) 💡 Technology Features Infotainment Features: N/A - This era of motorcycle predates modern infotainment systems. Features are mechanical and electrical rather than electronic. Driver Assistance Features: N/A - No electronic driver assistance features. Connectivity Features: N/A - No connectivity features. 🔧 Maintenance Service Intervals Engine Oil Change: Typically every 1,000-2,000 miles, or annually. The manual will provide precise intervals. Transmission Oil Change: Refer to manual for specific intervals, often tied to major service or mileage milestones. Fluid Specifications Engine Oil: Refer to manual for precise grade (e.g., SAE 50, 20W-50). Historically, straight-weight oils were common. Transmission Fluid: Gear oil of appropriate viscosity grade (refer to manual for specific type). Known Issues Valve Guides: Wear in valve guides can lead to oil consumption and smoke. Primary Chain Tensioner: Wear or failure of the primary chain tensioner can cause noise and drive train issues. Carburetor Leaks: Linkert carburetors can be prone to leaks...