Motorcycle Segment:
Custom Cruiser / Chopper-inspired
Target Audience:
Harley-Davidson enthusiasts, custom builders, mechanics specializing in vintage V-twins.
Competitors 1981:
Other American V-twins (e.g., Indian, Excelsior-Henderson, though less dominant), some British and European marques in specific segments.
Distinguishing Features:
The FXSB was part of Harley-Davidson's response to market trends, offering a lower, more custom look compared to traditional FL models, with belt drive and a disc brake rear.
Styling:
Sleek, custom styling with a lower profile, often featuring a kicked-out front fork and a rake angle.
Powertrain:
Robust Shovelhead V-twin engine, known for its torque and character.
Drivetrain:
Primary belt drive and final belt drive (a significant advancement for its time, offering a smoother, quieter ride).
Engine Overhaul:
Complete engine disassembly, inspection, repair, and reassembly procedures for the Shovelhead V-twin engine.
Transmission Service:
4-speed constant mesh transmission maintenance, repair, and adjustment, including clutch and primary drive.
Electrical System:
Wiring diagrams, component testing, troubleshooting for ignition, lighting, charging, and starting systems.
Fuel System:
Carburetor (likely Keihin butterfly or similar), fuel tank, fuel lines, and petcock service and adjustment.
Brake System:
Front and rear brake caliper, master cylinder, brake lines, and pad service and bleeding procedures.
Suspension:
Front fork (likely leading-axle) and rear shock absorber maintenance, adjustments, and rebuilds.
Frame And Body:
Frame inspection, bodywork repair, fender, fuel tank, seat, and handlebar mounting procedures.
Wheel And Tire:
Wheel bearing service, spoke tension adjustment, tire mounting, and balancing.
Routine Maintenance:
Oil changes, filter replacement, spark plug service, chain adjustment (if applicable), and general lubrication.
Troubleshooting Guides:
Diagnostic charts and step-by-step procedures for identifying and resolving common mechanical and electrical issues.
Engine Rebuild:
Detailed instructions for cylinder boring, piston replacement, valve seat grinding, and crankshaft inspection.
Transmission Rebuild:
Gear set inspection, bearing replacement, shift drum and pawl service, and clutch plate replacement.
Electrical Diagnostics:
Testing ignition timing, charging system output, starter motor operation, and lighting circuit integrity.
Brake Bleeding:
Step-by-step process for safely and effectively bleeding hydraulic brake systems.
Fork Seal Replacement:
Instructions for disassembling, cleaning, and replacing worn front fork seals.
Carburetor Tuning:
Jetting, idle speed, and mixture adjustment for optimal performance and fuel economy.
Depth Level:
Comprehensive (from basic maintenance to complete engine/transmission rebuilds and advanced electrical diagnostics).
Diagnostic Capability:
Enables owner/technician to perform in-depth troubleshooting using provided charts and specifications.
Rebuild Capability:
Supports full mechanical rebuilds of major components like the engine and transmission.
Wiring Diagram Detail:
Detailed, often color-coded, wiring diagrams for all electrical circuits.
Torque Specifications:
Precise torque values for critical fasteners throughout the motorcycle.
Tolerances And Clearances:
Specific measurements for engine internal clearances, bearing play, and other critical fits.
Searchability:
Likely text-searchable if the PDF was generated from a scanned document with OCR, otherwise image-based.
Print Readability:
Dependent on the source scan quality; typically designed for clarity of technical diagrams and text.
Binding Type Original Manual:
Spiral-bound or perfect-bound (for original printed versions).
Paper Type Original Manual:
Durable, often glossy or semi-gloss paper to withstand shop use and display diagrams clearly.
Engine Type:
Air-cooled, 45-degree V-twin
Engine Family:
Shovelhead
Displacement Cc:
1340 (80 cubic inches)
Bore X Stroke Mm:
3.496 x 4.25 (88.8 x 108.0)
Compression Ratio:
Approximately 8.0:1
Valvetrain:
Overhead Valves (OHV), pushrod actuated
Horsepower Hp:
Approximately 60-65 hp (estimated, varies with tuning and specific configuration)
Torque Ft Lb:
Approximately 75-80 ft-lb (estimated, peak torque around 3000-3500 RPM)
Carburetor:
Keihin Butterfly (likely CV or similar specific model for 1981)
Fuel Type:
Unleaded gasoline, minimum 87 octane recommended
Fuel Capacity Liters:
Approximately 13-14 liters (3.5-3.7 US gallons)
Transmission Type:
4-speed constant mesh
Gear Ratios:
Specific ratios would be detailed in the manual, typically around: 1st: 2.44, 2nd: 1.53, 3rd: 1.15, 4th: 1.00
Clutch Type:
Wet multi-plate
Primary Drive:
Duplex chain or cog-belt drive (1981 models moved towards belt drive)
Transmission Fluid Type:
Harley-Davidson Transmission Fluid, or equivalent (e.g., Bel-Ray, Spectro) - often a specific viscosity and friction modifier blend. Manual will specify.
Crash Test Ratings:
N/A (Motorcycles are not subjected to automotive crash testing standards).
Braking System:
Front: Single disc brake with hydraulic caliper. Rear: Disc brake with hydraulic caliper.
Lighting:
Halogen headlight, tail light, brake light, turn signals.
Frame Construction:
Steel tube frame, designed for stability and handling.
Wheel Type:
Spoked wheels, often with cast aluminum rims.
Oil Change Interval:
Typically every 2,500-3,000 miles or 6 months (refer to manual for precise mileage/time).
Primary Chain Adjustment:
Check and adjust every 5,000 miles or as needed.
Spark Plug Replacement:
Inspect every 5,000 miles, replace as needed (e.g., Champion H-series or NGK equivalents).
Brake Fluid Flush:
Recommended every 1-2 years, using DOT 4 fluid (check manual for confirmation).
Engine Oil Type:
Harley-Davidson 20W50 motorcycle oil or equivalent. Manual will specify exact type and capacity.
Primary Chain Case Oil:
Separate oil fill. Specification varies, often a lighter weight oil or dedicated primary oil. Manual is critical here.
Transmission Oil Type:
As noted in transmission section, specific HD transmission oil or equivalent. Capacity approximately 1 quart.
Oil Leaks:
Common with older Shovelheads due to gasket aging and crankcase seals; often requires gasket replacement and proper torque.
Carburetor Tuning Challenges:
Can be finicky; requires careful adjustment of idle mixture, jetting, and potentially recalibration for altitude or modifications.
Electrical Gremlins:
Aging wiring harnesses, loose connections, and failing original components (e.g., voltage regulator) can cause intermittent issues.
Rear Cylinder Overheating:
Can occur in heavy traffic; proper ignition timing and carburetor mixture are crucial.
Primary Chain Wear:
Needs regular inspection and adjustment to prevent premature wear or skipping.
Harley Davidson Founding:
Founded in 1903, Milwaukee, Wisconsin.
Shovelhead Era:
Shovelhead engine production ran from 1966 to 1984, preceding the Evolution engine.
Fx Series Origin:
The FX series (F = 74ci V-twin, X = Custom/Low Rider styling) represented Harley-Davidson's move into custom styling.
Fxsb Introduction:
The FXSB 'Sturgis' model was introduced in 1980, featuring the belt drive and custom styling, evolving from the FX Super Glide.
Production Location:
York, Pennsylvania, USA and Milwaukee, Wisconsin, USA assembly plants.
Key Production Years:
1980-1982 for the FXSB model.
Model Awards:
The FXSB, as part of the Shovelhead era and the FX series, is recognized for its role in defining the cruiser market and its iconic American styling, rather than specific annual awards.
Reliability Perception:
Reliability perceptions for Shovelheads vary. Enthusiasts often rate them highly for their character and rebuildability, but they require more diligent maintenance than modern bikes.
Emissions Standards:
Designed to meet U.S. EPA emissions standards of the era, which were significantly less stringent than today's.