Description:
The Harley-Davidson FLSTF Softail Fat Boy is an iconic cruiser known for its distinctive styling and robust V-twin performance. This manual serves as an essential resource for owners and technicians seeking to maintain, diagnose, and repair these classic models.
Comparison:
During its production run, the Fat Boy competed with other large-displacement cruisers from manufacturers like Indian and custom builders, offering a blend of retro styling and modern (for its time) V-twin technology.
Vehicle Appeal:
Chunky tires, wide handlebars, distinctive chrome accents, and the signature Harley-Davidson V-twin rumble contribute to its enduring appeal.
Manual Value:
Provides in-depth technical knowledge crucial for preserving the performance and longevity of this classic motorcycle.
Applicable Years:
1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999
Type:
Comprehensive Workshop Service & Repair Manual
Format:
Downloadable Digital Format (PDF)
Engine Mechanical:
Top End (Cylinders, Pistons, Heads), Bottom End (Crankcase, Crankshaft, Connecting Rods), Valve Train, Camshafts, Timing
Fuel System:
Carburetor (Keihin CV), Fuel Tank, Fuel Lines, Petcock
Ignition System:
Ignition Module, Ignition Coils, Spark Plugs, Wiring
Transmission:
5-Speed Gearbox (Disassembly, Assembly, Shifting Mechanism, Clutch Components)
Drivetrain:
Primary Drive (Clutch, Compensator), Final Drive (Belt Drive System)
Electrical System:
Wiring Diagrams, Battery, Charging System (Alternator, Regulator), Starting System (Starter Motor), Lighting, Gauges, Switches, Horn
Brakes:
Front and Rear Hydraulic Brakes (Calipers, Master Cylinders, Lines, Pads, Rotors)
Suspension:
Front Fork (Telescopic), Rear Shock Absorbers, Swingarm
Chassis Frame:
Frame Inspection, Steering Head, Wheel Bearings, Swingarm Pivot
Bodywork Fittings:
Fenders, Fuel Tank, Seat, Handlebars, Controls, Mirrors, Footboards
Routine Maintenance:
Oil Changes, Filter Replacements, Chain Adjustment (if applicable, though Fat Boy is belt drive), Tire Inflation, Lubrication Points
Engine Repair:
Top End Rebuild, Bottom End Rebuild, Carburetor Rebuild, Ignition Timing Adjustment
Transmission Repair:
Clutch Adjustment and Replacement, Gearbox Disassembly and Reassembly, Sprocket and Pulley Replacement
Electrical Diagnostics:
Troubleshooting Wiring Faults, Component Testing, Charging System Diagnosis
Brake Service:
Brake Pad Replacement, Brake Fluid Flush and Bleed, Caliper and Master Cylinder Overhaul
Suspension Service:
Fork Seal Replacement, Shock Absorber Replacement, Swingarm Bearing Service
Troubleshooting:
Diagnostic Flowcharts, Common Problem Identification, Symptom-Based Troubleshooting
Specifications And Torques:
All critical bolt torques, clearances, and measurements
Depth:
Complete overhaul and rebuild procedures, detailed diagnostic steps, component-level repair
Engine Type:
Air-cooled, Evolution V-Twin
Displacement:
1337 cc (81.7 cubic inches)
Bore X Stroke:
3.49 in x 4.25 in (88.9 mm x 108 mm)
Valvetrain:
OHV, 2 valves per cylinder, operated by pushrods and hydraulic lifters
Horsepower Approx:
~55-60 HP @ 5000 RPM (Estimate, varies by year/tune)
Torque Approx:
~70-75 lb-ft @ 3000 RPM (Estimate, varies by year/tune)
Carburetor:
Keihin CV (Constant Velocity) 40mm
Fuel Type:
Unleaded gasoline, 87 octane minimum
Oil Capacity:
3.5 US quarts (3.3 Liters) with filter change
Oil Type:
Harley-Davidson 20W50 motorcycle oil (or equivalent API SG/SH/SJ rated)
Type:
5-speed constant mesh, sequential manual transmission
Gear Ratios:
Typically: 1st: 9.23:1, 2nd: 6.41:1, 3rd: 4.77:1, 4th: 3.71:1, 5th: 3.15:1 (Ratios may vary slightly by year)
Transmission Options:
N/A (All FLSTF models for these years featured the 5-speed)
Clutch Type:
Wet, multi-plate, diaphragm spring
Primary Drive:
Duplex chain, chain primary drive with compensator sprocket
Final Drive:
Belt drive, 32mm belt
Transmission Oil Type:
Harley-Davidson Formula+ Transmission & Primary Chaincase Lubricant (or equivalent SAE 50 API GL-1)
Transmission Oil Capacity:
24 US fluid ounces (0.7 Liters)
Length:
Approx. 93.3 inches (2370 mm)
Width:
Approx. 38.0 inches (965 mm)
Height:
Approx. 51.2 inches (1300 mm)
Wheelbase:
Approx. 63.0 inches (1600 mm)
Ground Clearance:
Approx. 4.5 inches (114 mm)
Dry Weight:
Approx. 645 lbs (293 kg)
Gross Vehicle Weight Rating:
Approx. 1030 lbs (467 kg)
Fuel Capacity:
4.0 US gallons (15.1 Liters)
Front Tire Size:
130/90-16 M/C 67B
Rear Tire Size:
150/80-16 M/C 71B
Wheel Type:
Cast aluminum, chrome-plated, disc-style wheels
Wheel Size:
16-inch front and rear
Bolt Pattern:
5 x 4.5 inches (114.3 mm) PCD
Crash Test Ratings:
N/A (Motorcycle safety ratings are not standardized like automotive)
Braking System:
Dual-piston caliper front and rear hydraulic disc brakes
Lighting:
Halogen headlight, tail light, brake light, front and rear turn signals
Mirrors:
Large, easily adjustable mirrors for rear visibility
Chassis Design:
Low center of gravity for stability
First Service:
1,000 miles (1,600 km) or 6 months
Subsequent Services:
Every 5,000 miles (8,000 km) or 12 months thereafter
Belt Tension Check:
Recommended at every service, adjust as needed
Brake Fluid Flush:
Every 2 years
Engine Oil:
Harley-Davidson SYN3 Synthetic (preferred) or 20W50 conventional motorcycle oil
Primary Chaincase Oil:
Harley-Davidson Formula+ Transmission & Primary Chaincase Lubricant (or SAE 50 API GL-1)
Transmission Oil:
Harley-Davidson Formula+ Transmission & Primary Chaincase Lubricant (or SAE 50 API GL-1)
Brake Fluid:
DOT 4 (or DOT 5 if specified by a particular year, though DOT 4 is common for these).
Carburetor Issues:
CV Carburetor can sometimes suffer from diaphragm issues or jetting problems, especially if aftermarket modifications are made.
Electrical Connections:
Corrosion on connectors, particularly in humid environments, can lead to intermittent electrical issues.
Belt Drive:
While generally reliable, the belt can wear and require tension adjustment. Cracks can develop if improperly maintained or if debris gets caught.
Rear Shock ABSorbers:
Original shock absorbers may lose damping effectiveness over time, leading to a less controlled ride.
Heritage:
Harley-Davidson, founded in 1903, is one of the longest-standing motorcycle manufacturers globally, renowned for its V-twin engines and cruiser motorcycles.
Introduction:
The Softail platform was introduced in 1983, featuring hidden rear suspension to mimic the look of a rigid frame. The FLSTF Fat Boy variant was introduced in 1990, quickly becoming a style icon.
Styling Influence:
The Fat Boy's design was heavily influenced by the Harley-Davidson Hydra-Glide and the post-war civilian version of the military's Liberator motorcycle.
Key Design Elements:
Fat tires (hence the name), full fenders, teardrop gas tank, and extensive chrome plating defined the model.
Manufacturing Location:
York, Pennsylvania, USA (and Milwaukee, Wisconsin, USA for many components)
