🏷️ Basic Information

Make:

Harley-Davidson

Model:

FXS Low Rider

Year:

1978

Engine Type:

Shovelhead V-Twin

Generation Identifier:

Shovelhead Era

Vin Decoder Notes:

VIN structure typically starts with 3H0...

👋 Introduction

Market Segment:

American cruiser motorcycle, performance-oriented custom build.

Competitors:

Other custom or factory choppers and cruisers of the era, though Harley-Davidson held a dominant position in this segment.

Design Philosophy:

Emphasis on power, distinctive styling, and rider engagement; the FXS represented a factory-custom approach.

Shovellhead Legacy:

The Shovelhead engine, known for its distinctive sound and robust performance, was a hallmark of Harley-Davidson's evolution in the late 60s and 70s.

Manual Value:

Essential for owners and mechanics to maintain, diagnose, and repair the FXS Low Rider, preserving its iconic status and performance.

📋 Manual Details

Coverage:

All FXS Shovelhead models for 1978

Page Count:

Estimated 500-700 pages (typical for comprehensive workshop manuals of this era)

Manual Type:

Workshop Service Repair Manual

Language:

English

Format:

PDF Download

📖 Manual Coverage

Engine:

Detailed breakdown of Shovelhead engine, including top end (cylinders, heads, valves), bottom end (crankcase, crankshaft, connecting rods), lubrication system, and cooling system.

Fuel System:

Carburetor (likely Keihin Butterfly or similar), fuel lines, fuel tank, petcock, and fuel pump (if equipped).

Ignition System:

Points ignition system, ignition coil, spark plugs, wiring diagrams, timing procedures, and troubleshooting.

Transmission:

4-speed constant mesh transmission, clutch assembly, primary drive, and final drive.

Electrical System:

Wiring diagrams, battery, charging system (generator/alternator), starter motor, lighting (headlight, taillight, turn signals), horn, and switches.

Brakes:

Front and rear brake system components, hydraulic lines, brake fluid, master cylinders, calipers, and bleeding procedures.

Suspension:

Front fork (leading-link or conventional telescopic), rear swingarm, shock absorbers, and associated bushings/bearings.

Frame And Bodywork:

Frame inspection and repair, body panels, fenders, fuel tank mounting, seat assembly, and handlebars.

Wheels And Tires:

Wheel bearing service, tire selection, and mounting procedures.

Maintenance:

Regular service checks, oil changes, filter replacements, chain adjustment, lubrication points, and pre-ride inspections.

Troubleshooting:

Systematic diagnostic guides for common and uncommon issues, symptom-based troubleshooting charts.

Repair:

Step-by-step instructions for component disassembly, inspection, repair, and reassembly of all major systems.

Overhaul:

Complete engine and transmission overhaul procedures, including torque specifications and clearances.

Adjustment:

Carburetor adjustment, ignition timing, clutch adjustment, and brake lever adjustment.

Depth:

Comprehensive, from routine maintenance to full engine and transmission rebuilds. Includes diagnostic procedures and specifications for expert-level repairs.

📊 Manual Specifications

File Format:

PDF

Searchability:

Likely text-searchable (if digitally created or scanned with OCR).

Print Quality:

High-resolution scans suitable for printing high-quality documents.

Binding Type:

N/A (Digital download, user prints and binds)

Paper Type:

N/A (Digital download, user prints on preferred paper type)

⚙️ Engine Specifications

Engine Family:

Shovelhead

Engine Configuration:

Air-cooled, 45-degree V-twin

Displacement:

74 cubic inches (1200cc)

Bore X Stroke:

Approx. 3.4375 in x 4.00 in (87.3 mm x 101.6 mm)

Compression Ratio:

Typically 8.0:1 or 8.5:1 for 1978 models

Valve Train:

Overhead valves (OHV), pushrod actuated

Cylinder Heads:

Cast iron

Pistons:

Cast aluminum

Horsepower:

Estimated 60-65 hp at rear wheel (specifications vary by tuning and dyno)

Torque:

Estimated 75-80 ft-lbs (102-108 Nm) at approx. 3000-4000 RPM

Carburetor Type:

Keihin Butterfly (e.g., BD or similar) or Linkert (less common for FX models by '78)

Fuel Octane Rating:

Minimum 91 octane (AKI) recommended for optimal performance and to prevent knocking

Oil Type:

Harley-Davidson 20W50 or equivalent API SG/SH rated motorcycle oil

Oil Capacity:

Approx. 4 US quarts (3.8 liters) including primary and transmission

Ignition Type:

Contact breaker points system

Spark Plug Gap:

0.030-0.040 inches (0.76-1.02 mm)

🔧 Transmission

Transmission Type:

4-speed constant mesh, foot shift, hand clutch

Gear Ratios:

Specific ratios would be detailed in the manual, but typical for the era were aggressive for performance.

Primary Drive:

Duplex chain, wet clutch

Clutch Type:

Wet, multi-plate

Transmission Fluid Type:

Harley-Davidson Transmission Lubricant (e.g., 80W90 gear oil) or equivalent

Transmission Fluid Capacity:

Approx. 1 US quart (0.95 liters)

📐 Dimensions

Wheelbase:

Approx. 62.5 inches (1588 mm)

Overall Length:

Approx. 89.0 inches (2261 mm)

Dry Weight:

Approx. 560 lbs (254 kg)

Gross Vehicle Weight Rating:

Typically around 850 lbs (386 kg)

🛡️ Safety Features

Safety Standards:

Reflects 1970s safety standards; lacks modern ABS, traction control, or advanced airbags.

Braking System:

Hydraulic disc front brake, mechanical drum rear brake (typical for FXS models of this year).

Lighting:

Halogen headlight, incandescent taillight and turn signals.

Frame Construction:

Steel frame designed for stability and rider feedback.

💡 Technology Features

Infotainment System:

No integrated infotainment system. Relies on analog gauges (speedometer, tachometer if fitted) and basic controls.

Driver Assistance Features:

None.

Connectivity:

No electronic connectivity features.

🔧 Maintenance

Oil Change Interval:

Every 2,000-3,000 miles (3,200-4,800 km) or annually, whichever comes first.

Primary Chain Tension Check:

Every 1,000 miles (1,600 km)

Spark Plug Replacement:

Every 5,000-10,000 miles (8,000-16,000 km) depending on plug type and condition.

Brake Fluid Flush:

Every 1-2 years

Engine Oil:

Harley-Davidson 20W50 Motorcycle Oil or equivalent API SG/SH

Transmission Oil:

Harley-Davidson Transmission Lubricant 80W90 or equivalent API GL-5

Primary Chain Case Oil:

Harley-Davidson Primary Chain Lubricant or 50W motorcycle oil

Brake Fluid:

DOT 3 or DOT 4 hydraulic brake fluid (check specific caliper manufacturer recommendations if not original)

Shovelhead Engine:

Oil leaks (particularly from pushrod tubes and rocker boxes), oil consumption, cam wear, and potential for valve seat recession on older engines.

Electrical System:

Aging wiring insulation, loose connections, generator/regulator issues, and starter solenoid failures.

Carburetion:

Carburetor adjustments needed for altitude/temperature changes, accelerator pump issues.

Transmission:

Clutch drag, worn shift forks, and occasional gear engagement issues.

Air Filter Part Number:

Specific part number would be found in the manual or on the filter itself (e.g., aftermarket K&N or original style paper filter).

Oil Filter Part Number:

N/A for most 1978 Shovelheads which typically used an oil screen/filter in the crankcase breather or were dry-sump without a cartridge filter.

Spark Plug Part Number:

Champion RN4C or equivalent NGK equivalent.

📚 Vehicle History

Brand History:

Harley-Davidson, founded in 1903, is an iconic American motorcycle manufacturer with a rich history of producing V-twin motorcycles for performance, utility, and leisure.

Fxs Lineage:

The FX chassis was introduced in the early 1970s as a hybrid, combining elements of the FL (Electra Glide) and XL (Sportster) platforms. The FXS Low Rider, launched in 1977, offered a lower seat height and custom styling, quickly becoming a popular model.

Manufacturing Location:

York, Pennsylvania, USA

Significance Of 1978:

Represents a key year in the Shovelhead era, showcasing refined engineering and styling that cemented Harley-Davidson's identity.

🏆 Awards & Recognition

Industry Acclaim:

Harley-Davidson motorcycles of this era, particularly custom models like the FXS, were often celebrated for their styling and raw performance, becoming cultural icons.