🏷️ Basic Information Identification Make: Harley-Davidson Model: Duo Glide Model Year: 1958-1959 Codes Internal Model Code: FL (for the Duo-Glide designation, often encompassing FLH variations) 👋 Introduction Market Position Product Type: Essential reference for owners and restorers of 1958-1959 Harley-Davidson Duo Glide motorcycles. Competitive Analysis Value Proposition: Provides significant cost savings by enabling owners to perform maintenance and repairs themselves, reducing reliance on specialized (and often costly) vintage motorcycle mechanics. Key Features Manual Benefits: Step-by-step instructions, clear pictures, detailed wiring diagrams, comprehensive coverage of all services and repairs. User Experience: Empowers owners to understand and maintain their classic Harley-Davidson, fostering a deeper connection with the machine. 📋 Manual Details Coverage Areas Primary Coverage: Service, Repair, Maintenance, Troubleshooting, Electrical Diagrams, Specifications Secondary Coverage: Parts Identification, Routine Adjustments, Overhaul Procedures Page Count Estimated Page Count: Varies by specific edition, typically 300-500+ pages for a comprehensive WSM Manual Type Manual Type: Workshop Service Manual (WSM) / Service Repair Manual Language Language: English Format File Format: PDF Digital Delivery: Instant Download Print Quality: Full Printable Software Requirements: Adobe PDF Reader Compatibility: All Versions of Windows & Mac 📖 Manual Coverage Systems Covered Engine: Panhead (90° V-twin) Engine: Overhaul, tuning, lubrication, cooling, ignition timing, carburetor adjustments, valve adjustments, cylinder head service, piston/ring replacement, crankshaft/connecting rod inspection. Transmission: 4-Speed Constant Mesh Transmission: Disassembly, assembly, clutch service, gear inspection, shift linkage adjustments, lubrication. Frame And Suspension: Front Fork (Hydra-Glide), Rear Swingarm Suspension: Overhaul, fluid changes, seal replacement, shock absorber service, steering head bearing adjustment. Electrical System: Wiring Diagrams, Ignition System (Magneto/Coil), Lighting (Headlight, Taillight, Signals), Charging System (Generator/Regulator), Battery Maintenance, Switches, Horn. Fuel System: Carburetor Service (e.g., Linkert M-series), Fuel Tank, Fuel Lines, Fuel Valve. Braking System: Drum Brakes (Front and Rear): Brake shoe replacement, brake rod adjustment, linkage maintenance. Bodywork And Trim: Fenders, Fuel Tank, Seat, Handlebars, Controls, Paint and Chrome Care. Procedures Included Routine Maintenance: Oil changes, filter replacement (if applicable), lubrication points, spark plug replacement, tire pressure checks, chain adjustment. Troubleshooting: Diagnostic charts, common problems and solutions, symptom-based troubleshooting. Repair And Rebuild: Step-by-step instructions for engine, transmission, suspension, and electrical component overhauls and repairs. Adjustments: Carburetor tuning, ignition timing, clutch adjustment, brake linkage, throttle and clutch cables. Technical Specifications: Torque values, clearances, fluid capacities, ignition timing settings, carburetor jet sizes. Technical Depth Depth Of Coverage: Comprehensive; suitable for both experienced mechanics and dedicated DIY enthusiasts aiming for full restoration or major repairs. 📊 Manual Specifications File Format File Format: PDF Print Quality Print Quality: High-resolution, suitable for clear printing of all diagrams and text. Binding Type Binding Type: Digital Download (printable pages) Paper Type Paper Type For Printing: Standard printer paper (user choice) ⚙️ Engine Specifications Primary Engine Engine Type: Air-cooled, four-stroke, OHV V-twin (Panhead) Displacement: 74 cubic inches (1200 cc) Bore X Stroke: 3.4375 in x 4.00 in (87.3 mm x 101.6 mm) Compression Ratio: Approximately 7.0:1 (varies slightly by model year and variant) Performance Horsepower: Approx. 50-55 HP @ 4800-5000 RPM (estimated, factory figures often not precisely stated for this era) Torque: Not explicitly stated in modern terms, but designed for strong low-end and mid-range torque delivery. Fuel System Carburetor: Linkert M-series (e.g., M74B, M74C) Fuel Type: Premium Unleaded Gasoline (Octane rating suitable for the era's engines, typically 90+ octane) 🔧 Transmission Standard Transmission Type: 4-speed constant mesh Clutch Type: Dry multi-plate Features Gearbox Operation: Foot shift, hand clutch 📐 Dimensions Exterior Wheelbase: Approx. 60.6 inches (1539 mm) Weights Dry Weight: Approx. 540-570 lbs (245-259 kg) depending on model and equipment 🛡️ Safety Features Ratings Safety Standards Era: Reflects safety standards of the late 1950s; limited electronic safety features. Active Features Braking System: Mechanical drum brakes (front and rear) Passive Features Lighting: Headlight, taillight, brake light, optional turn signals (depending on market and factory fitment). 💡 Technology Features Infotainment Infotainment Features: N/A (Vintage motorcycle, no modern infotainment systems) Driver Assistance Driver Assistance Features: N/A (Vintage motorcycle) Connectivity Connectivity Features: N/A (Vintage motorcycle) 🔧 Maintenance Service Intervals Engine Oil Change: Typically every 1,000 - 1,500 miles or annually. Manual will specify exact interval and procedure. Primary Chain Tension: Regular checks and adjustments recommended, especially during initial break-in and at prescribed mileage intervals. Spark Plugs: Inspect and gap every few thousand miles, replace as needed. Fluid Specifications Engine Oil: Harley-Davidson recommended 50W or 60W motorcycle oil (refer to manual for precise specification and type). Transmission Oil: API GL-3 or GL-4 gear oil (e.g., Harley-Davidson 80W-90 or equivalent). Primary Chain Case Oil: Harley-Davidson Primary Chain Lubricant or equivalent. Fork Oil: Specific weight fork oil (e.g., 10W or 15W, refer to manual). Known Issues Panhead Engine: Oil leaks are common due to vintage seals and gaskets. Valve guide wear can occur. Generator charging system can require maintenance. Transmission: Shifting can be less precise than modern transmissions. Clutch adjustment is critical. Electrical: Wiring insulation can degrade with...