This manual provides comprehensive service and repair information for the 1981 FXSB. Known for its distinctive Shovelhead V-Twin engine and classic cruiser styling, the FXSB represents a significant era in American motorcycle manufacturing. This model is highly collectible, appreciated by enthusiasts for its raw power, iconic sound, and the engineering heritage of its manufacturer. This guide is designed to assist owners and technicians in maintaining the authenticity and optimal performance of this legendary machine. The scope of this factory service manual is extensive, covering complete factory service and repair procedures for all major systems. It details engine overhaul, transmission maintenance, drivetrain servicing, suspension and brake system repairs, and electrical system diagnostics. Additionally, the manual includes step-by-step instructions for disassembly and reassembly, scheduled maintenance, troubleshooting common issues like carburetor tuning and ignition timing, and essential technical specifications. This resource is an invaluable tool for ensuring the longevity and proper functioning of your 1981 FXSB. 🏷️ Basic Information Identification Make: Harley-Davidson Model: FXSB Year: 1981 Product Name: Harley Davidson Shovelhead FXSB 1981 Service Repair Manual PDF Download 👋 Introduction Market Position Target Audience: Harley-Davidson owners, custom builders, vintage motorcycle enthusiasts, and independent repair shops specializing in classic HD models Competitive Analysis Value Proposition: Provides essential factory-level technical data for maintaining and repairing a iconic American motorcycle, ensuring authenticity and optimal performance. Key Features Manual Advantage: Direct access to official factory procedures and specifications, crucial for the Shovelhead era's unique engineering. 📋 Manual Details Coverage Areas Primary Coverage: Complete Factory Service and Repair Secondary Coverage: Workshop, Maintenance, Troubleshooting, Reassembly Page Count Estimated Pages: Hundreds (Exact count not specified, but implied to be comprehensive) Manual Type Type: Factory Service Manual / Workshop Manual Language Language: English Format Format: PDF Download 📖 Manual Coverage Systems Covered Engine: Shovelhead V-Twin (Disassembly, Assembly, Tuning, Carburetion, Ignition, Lubrication) Transmission: 4-Speed Gearbox (Removal, Installation, Overhaul, Fluid Specifications) Drivetrain: Primary Drive, Belt Drive, Final Drive (Clutch, Sprockets, Chain Maintenance) Suspension: Front Forks (Telescopic), Rear Shocks (Spring-Assisted, Preload Adjustment) Brakes: Front Disc Brake, Rear Drum Brake (Service, Adjustment, Pad/Shoe Replacement) Electrical System: Ignition System (Points, Coil, Spark Plugs), Charging System (Alternator, Regulator), Lighting, Battery Service, Wiring Diagrams Fuel System: Carburetor (Keihin Butterfly, Tuning), Fuel Tank, Fuel Lines, Petcock Frame And Body: Chassis Components, Fenders, Fuel Tank Mounting, Seat, Handlebars Procedures Included Maintenance: Scheduled Maintenance, Lubrication Points, Fluid Changes, Filter Replacements, Tire Pressure Checks Troubleshooting: Diagnostic Charts, Symptom-Based Troubleshooting Guides for Engine, Electrical, and Drivetrain Issues Repair: Engine Overhaul, Transmission Rebuild, Fork Seal Replacement, Brake Caliper Service, Electrical Component Repair Disassembly And Assembly: Step-by-step instructions for complete component disassembly and reassembly Technical Depth Depth: Comprehensive Factory Level - Suitable for DIY enthusiasts and professional mechanics Diagnostic Capabilities: Advanced diagnostics for all major systems, including ignition timing and carburetor jetting 📊 Manual Specifications File Format Format: PDF (Portable Document Format) Searchability: Typically searchable text-based PDF, allowing quick information retrieval Print Quality Printability: Designed to be printed, with full page coverage for easy binding Binding Type Suggested Binding: Comb binding, spiral binding, or binder insertion (user dependent) Paper Type Recommended Paper: Standard printer paper (8.5"x11" or A4), heavier stock for frequently used sections ⚙️ Engine Specifications Primary Engine Engine Type: Shovelhead V-Twin, Air-Cooled Displacement: 73.7 cubic inches (1208cc) - Standard for FX models of this era Bore X Stroke: 3.4375 in x 4.25 in (87.3 mm x 108.0 mm) Compression Ratio: Typically around 8.5:1 (can vary slightly based on specific build/tuning) Performance Horsepower Approx: ~55-60 HP (Varies based on tuning and specific configuration) Torque Approx: ~65-70 ft-lbs (Varies based on tuning and specific configuration) Fuel System Carburetor Type: Keihin Butterfly (e.g., Keihin CV or early butterfly models like 36mm, depending on exact fitment) Fuel Type: Unleaded gasoline, Octane rating as per manufacturer recommendation (typically 91+ RON / 87+ MON) Lubrication Oil Type: Specific Harley-Davidson 20W50 motorcycle oil or equivalent (e.g., SYN3 or other high-quality V-twin specific oil) Oil Capacity Engine Trans: Approximately 3 quarts (engine oil also lubricates transmission in Shovelheads) 🔧 Transmission Standard Transmission Type: 4-Speed Constant Mesh, Foot Shift, Left-Side Drive Optional Optional Transmissions: N/A for factory FXSB 1981, 4-speed was standard. Features Clutch Type: Wet, Multi-plate, Cable-actuated Transmission Fluid: Harley-Davidson primary chaincase lubricant or equivalent Gear Ratios: Specific ratios detailed in the manual, critical for performance tuning. 📐 Dimensions Exterior Wheelbase: ~61.5 inches (1562 mm) Length: ~87 inches (2210 mm) Weights Dry Weight: ~570 lbs (258 kg) Gross Vehicle Weight Rating: Not typically specified in the same way as modern vehicles; manual will detail load capacities. Tires Front Tire Size: Commonly 3.50-19 or similar bias-ply Rear Tire Size: Commonly 5.10-16 or similar bias-ply Wheels Wheel Type: Spoked, typically 19-inch front, 16-inch rear Bolt Pattern: N/A for spoke wheels; hub mounting details provided in manual. 🛡️ Safety Features Ratings Crash Test Ratings: N/A - Motorcycles are not subjected to standardized crash testing...