🏷️ Basic Information Identification Make: Harley-Davidson Model: EL "Knucklehead" Model Nickname: Knucklehead Product Name: Harley Davidson 1940-1947 Knucklehead Service Repair Manual 👋 Introduction Market Position Target Audience: Harley-Davidson owners, restorers, mechanics specializing in vintage motorcycles. Competitive Analysis Value Proposition: Provides critical technical information for maintaining and repairing a classic and iconic American motorcycle, ensuring authenticity and proper function. Key Features Technical Accuracy: Information sourced directly from the manufacturer, ensuring accuracy and adherence to original specifications. Ease Of Access: Instant download provides immediate access to vital repair and maintenance information. 📋 Manual Details Coverage Areas Primary Coverage: Service, Repair, Maintenance Secondary Coverage: Technical Specifications, Diagrams, Assembly, Disassembly, Troubleshooting, Diagnostics Page Count Estimated Pages: Likely several hundred (exact number not provided, but comprehensive for the era). Manual Type Type: Factory Service Manual / Repair Manual Language Language: English Format Format: Digital Download (likely PDF) 📖 Manual Coverage Systems Covered Engine: Valve train, lubrication system, ignition system, fuel system, cooling (air-cooled), engine disassembly and reassembly, timing. Transmission: 4-speed constant mesh gearbox, clutch operation, maintenance, repair, disassembly, and reassembly. Electrical: Lighting system, ignition coil, distributor, wiring diagrams, battery maintenance, starter system, generator. Frame And Suspension: Front fork (Spring fork), rear suspension (rigid frame), wheel bearings, steering head bearings. Brakes: Front and rear drum brake systems, adjustment, maintenance, and repair. Fuel And Exhaust: Carburetor (e.g., Linkert), fuel tank, fuel lines, exhaust system. Bodywork And Trim: Fenders, fuel tank mounting, seat assembly, handlebars, controls. Procedures Included Maintenance: Regular servicing, lubrication schedules, filter changes, tune-ups, pre-ride inspections. Repair: Engine rebuilds, transmission overhauls, electrical component replacement, brake system repairs, fork rebuilding. Diagnostics: Troubleshooting common problems, identifying causes of poor performance, electrical fault finding. Adjustments: Carburetor tuning, ignition timing, clutch adjustment, brake adjustment, valve lash adjustment. Technical Depth Depth: Comprehensive, suitable for skilled mechanics and experienced enthusiasts. Covers disassembly, inspection, repair, and reassembly of all major components. 📊 Manual Specifications File Format File Type: Digital Download (most likely PDF) Searchability: Likely text-searchable if properly OCR'd. Print Quality Printability: Printable sections are supported, allowing for physical copy creation. Binding Type Binding: N/A (Digital Download) Paper Type Paper Quality: N/A (Digital Download) ⚙️ Engine Specifications Primary Engine Engine Type: OHV (Overhead Valve) V-Twin Displacement Cu In: 61 cubic inches (for EL models) Displacement Cc: 1000cc (for EL models) Bore X Stroke: 3.25 x 3.625 inches (for EL models) Performance Horsepower Est: Approximately 25-30 HP (at that era's RPM range) Torque Est: Not explicitly stated but substantial for the displacement. Fuel System Carburetor: Linkert M-series carburetor (specific model varies by year and configuration) Fuel Type: Gasoline Lubrication System Type: Dry Sump Lubrication System Ignition System Type: Battery and Coil Ignition (with distributor) 🔧 Transmission Standard Type: 4-Speed Manual Constant Mesh Features Clutch Type: Wet multi-plate clutch Gear Ratios: Specific gear ratios are detailed within the manual. 📐 Dimensions Exterior Wheelbase In: Approximately 57.5 inches (varies slightly by year/model). Weights Dry Weight Lbs: Approximately 515-560 lbs (varies by model and equipment). Fuel Capacity Gal: Approximately 3.5 gallons (for standard tank). 🛡️ Safety Features Active Features Brakes: Drum brakes front and rear. Lighting: Headlight, taillight, and brake light. Passive Features Frame: Robust steel frame designed for stability. 💡 Technology Features Infotainment System: N/A (This era of motorcycle predates modern infotainment systems). Driver Assistance Features: N/A (No electronic driver assistance features). Connectivity Features: N/A (No electronic connectivity features). 🔧 Maintenance Service Intervals Oil Change: Typically every 1,000-1,500 miles, with specific recommendations in the manual. Tune Up: As needed, but generally includes spark plug checks, ignition timing, and carburetor adjustments. Fluid Specifications Engine Oil: SAE 50 or SAE 60 motorcycle-specific oil (consult manual for exact specifications and viscosity based on temperature). Transmission Oil: Dedicated Harley-Davidson transmission lubricant or equivalent (specific type detailed in manual). Primary Chain Case Oil: Harley-Davidson primary chain lubricant or equivalent. Known Issues Oil Leaks: Common in vintage motorcycles due to aging seals and gaskets. Manual will detail seal replacement procedures. Carburetor Tuning: Linkert carburetors can be finicky; proper adjustment is crucial for optimal performance. Valve Adjustment: Regular valve lash adjustments are necessary to maintain proper engine operation. 📚 Vehicle History Brand Heritage Heritage: Harley-Davidson is an iconic American motorcycle manufacturer with a long history of producing powerful and durable machines. Model Evolution Knucklehead Era: The Knucklehead, produced from 1936 to 1947, was a revolutionary design for Harley-Davidson, featuring a more integrated engine and transmission, and the distinctive 'knuckle' shape of the rocker boxes. Production Production Period: 1940-1947 (this manual covers this specific range) War Time Production: During WWII, Harley-Davidson produced many motorcycles for military use, including military versions of the Knucklehead (e.g., WLA), though civilian models continued to be produced as well. 🏆 Awards & Recognition Recognitions Status: The Knucklehead is considered a highly desirable and iconic motorcycle, a significant part of American automotive history.