Target Audience:
Harley-Davidson FXB Shovelhead owners and independent mechanics seeking to perform service, maintenance, and repairs.
Value Proposition:
Provides essential technical data and procedural guidance for maintaining and repairing a classic American motorcycle, offering significant cost savings over dealership service.
Digital Accessibility:
Convenient access and portability of repair information via PDF format.
Historical Relevance:
Documents the specific technicalities of the 1981 Shovelhead model, a significant year in Harley-Davidson's evolution.
Primary Coverage:
Service, Repair, Maintenance
Secondary Coverage:
Troubleshooting, Diagnostics, Specifications
Estimated Pages:
300-400 (typical for this era's comprehensive manuals)
Type:
Factory Service Manual / Repair Manual
Engine:
Shovelhead V-Twin Engine (including top end, bottom end, ignition, carburetor, oil system)
Transmission:
4-Speed Constant Mesh (including clutch, primary drive, gearbox, shifting mechanism)
Chassis:
Frame, Forks, Swingarm, Suspension components
Electrical:
Ignition system (points, coil, condenser), Lighting, Charging system (generator/alternator, voltage regulator), Battery, Wiring diagrams
Brakes:
Front and Rear Brake Systems (hydraulic, mechanical components, fluid specifications)
Fuel System:
Fuel Tank, Fuel Lines, Carburetor (e.g., Keihin Butterfly, Linkert) and its components
Bodywork:
Fenders, Fuel Tank, Seat assembly, Handlebars, Controls
Maintenance:
Oil changes, Filter replacement, Spark plug maintenance, Chain adjustment, Lubrication points
Repair:
Engine rebuilds (top end, bottom end), Transmission overhauls, Clutch replacement, Brake system service, Electrical component replacement
Troubleshooting:
Diagnostic procedures for common starting, running, and electrical issues
Adjustments:
Carburetor tuning, Ignition timing, Clutch and brake lever adjustments, Chain tension
Depth:
Comprehensive, covering from routine maintenance to complete engine and transmission rebuilds.
Diagnostic Level:
Detailed diagnostic charts and symptom-based troubleshooting guides.
Rebuild Procedures:
Step-by-step instructions for major component overhauls with torque specifications and tolerances.
Engine Type:
Air-cooled, 45-degree V-twin
Displacement:
73.7 cubic inches (1207 cc) - commonly referred to as 1200cc
Bore X Stroke:
3.4375 in x 4.25 in (87.3 mm x 108.0 mm) - typical for 1200cc Shovelheads
Compression Ratio:
Typically around 8.0:1 for standard models of this era
Valve Train:
Overhead valve (OHV) with pushrods
Horsepower:
Approximately 60-65 HP (estimated at crankshaft, actual may vary)
Torque:
Approximately 65-70 ft-lbs (estimated at crankshaft, actual may vary)
Carburetor:
Likely a Keihin Butterfly (CV - Constant Velocity) or a Linkert carburetor, depending on specific sub-model or factory options.
Fuel Type:
Unleaded gasoline (91 octane or higher recommended for optimal performance and longevity)
Type:
Battery and Coil system with Breaker Points ignition. Electronic ignition (e.g., points replacement kits) may have been aftermarket options.
Type:
Dry Sump system with oil tank separate from the crankcase.
Oil Capacity:
Approximately 3 US quarts (2.8 liters) including filter, plus reserve in the tank.
Recommended Oil:
Viscosity: 20W50 (common for Shovelheads). Specific Harley-Davidson or motorcycle-specific oil formulations recommended.
Type:
4-speed Constant Mesh
Drive Type:
Chain drive (primary) to clutch, Belt drive (secondary) from transmission to rear wheel.
Clutch Type:
Wet multi-plate, diaphragm spring
Transmission Fluid:
Specific Harley-Davidson transmission lubricant or equivalent SAE 80W-90 gear oil recommended. Manual will specify precise type and capacity.
Oil Change Interval:
Typically every 2,000-3,000 miles or 6 months, whichever comes first, depending on riding conditions. Manual will provide definitive intervals.
Major Service:
Recommended for valve adjustments, spark plug replacement, and comprehensive inspection at intervals around 5,000-10,000 miles.
Primary Chain Case Oil:
Harley-Davidson primary chaincase lubricant or equivalent SAE 20W-50 motor oil (often shared with the engine in this era).
Brake Fluid:
DOT 4 or DOT 5 brake fluid, depending on original specification and system materials. Manual will specify DOT rating.
Oil Leaks:
Common for Shovelhead engines due to aging seals and gaskets. Manual covers seal replacement procedures.
Carburetor Tuning:
Carburetors of this era (especially Linkert or early Keihin) require periodic tuning for optimal performance and fuel economy. Manual details adjustment procedures.
Charging System:
Older generators and voltage regulators can be prone to failure. Manual details testing and replacement.
Transmission Shifting:
Potential for stiff shifting or false neutrals; manual covers internal transmission adjustments and repairs.
Heritage:
Harley-Davidson, founded in 1903, is renowned for its iconic cruiser motorcycles, built on a legacy of American engineering and custom culture.
Shovelhead Lineage:
The Shovelhead engine, introduced in 1966, was a successor to the Panhead and a precursor to the Evolution (Evo) engine. The FXB model typically represents a factory custom or FX-based platform.
1981 Significance:
1981 marked the transition period for Harley-Davidson, with development of the Evolution engine underway, making the 1981 Shovelhead a representative of the final iterations of this classic engine design.
Production Era:
Shovelhead engine production: 1966-1984. FXB models would fall within this range, with 1981 being a specific year.
