Model:
FLSTF Softail Fat Boy
Years Covered:
1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999
Category:
Cruiser Motorcycle
Target Audience:
Harley-Davidson FLSTF Softail Fat Boy owners, technicians, and enthusiasts seeking detailed service and repair information
Comparison:
The Fat Boy was positioned as a retro-styled cruiser with a distinctive look, often featuring wider tires and chrome accents, appealing to riders seeking classic styling and a comfortable riding experience. This manual provides the essential technical data needed to maintain and repair this iconic model.
Model Appeal:
Known for its wide front tire, chrome detailing, and classic styling, the FLSTF Softail Fat Boy is a desirable motorcycle that benefits from thorough maintenance.
Engine:
Engine teardown, assembly, tuning, lubrication, cooling system, ignition system, carburetor (Keihin CV), fuel delivery
Transmission:
Clutch, primary drive, transmission (5-speed, Cruise Drive), final drive, lubrication, maintenance, repair
Chassis And Suspension:
Frame, swingarm, front forks (Showabe or similar), rear shock absorbers, steering head bearings, wheel bearings
Brakes:
Front and rear brake systems, hydraulic lines, master cylinders, calipers, pads, rotors, bleeding procedures
Electrical System:
Battery, charging system (stator, regulator/rectifier), starting system (starter motor, solenoid), lighting, ignition switches, fuses, wiring diagrams, diagnostic codes
Bodywork And Trim:
Fuel tank, fenders, seat, handlebars, controls, instrumentation, exhaust system, chrome components, cosmetic repairs
Maintenance:
Routine service checks, oil changes, filter replacements, spark plug changes, chain adjustment (if applicable, though belt drive is common), brake fluid changes, tire pressure checks
Troubleshooting:
Diagnostic procedures for common issues, fault finding for electrical and mechanical systems, carburetor adjustment and troubleshooting
Repair:
Detailed step-by-step repair instructions for all major components, including engine rebuild, transmission overhaul, suspension servicing, and electrical system repairs
Depth:
Comprehensive, covering everything from basic preventative maintenance to complete engine and transmission rebuilds. Includes detailed torque specifications, clearances, and diagnostic flowcharts.
Type:
Evolution (Evo) V-Twin, Air-cooled
Displacement:
1338 cc (82 cubic inches)
Bore X Stroke:
3.497 in x 4.250 in (88.8 mm x 107.95 mm)
Compression Ratio:
8.8:1 (typical)
Horsepower:
Approx. 55-60 HP @ 5000 RPM (estimate, not officially published widely for these years)
Torque:
Approx. 65-70 ft-lbs @ 2350 RPM (estimate)
Carburetor:
Keihin CV (Constant Velocity) 40 mm
Fuel Type:
Unleaded gasoline, minimum 87 octane
Type:
5-speed constant mesh, manual
Primary Drive:
Duplex chain, wet clutch
Gear Ratios:
Refer to manual for specific ratios (typically 9.01:1 in 1st, 6.03:1 in 2nd, 4.72:1 in 3rd, 3.76:1 in 4th, 3.15:1 in 5th)
Transmission Fluid:
Harley-Davidson transmission fluid or SAE 80W-90 gear oil (check manual for specific recommendations)
Crash Test Results:
N/A (Motorcycles are not subject to standardized car crash tests)
Braking:
Hydraulic disc brakes, front and rear
Lighting:
Headlight, taillight, brake light, turn signals
Instrumentation:
Speedometer, tachometer (on some models/aftermarket), fuel gauge, oil pressure light, neutral indicator, high beam indicator, turn signal indicators
Oil Change:
Every 2,500-5,000 miles or 6 months (refer to manual for precise interval based on riding conditions)
Primary Chain Tensioner Check:
Check at every oil change, adjust or replace as needed (especially important for early Evo models)
Spark Plug Replacement:
Every 10,000-15,000 miles
Brake Fluid Flush:
Every 2 years
Engine Oil:
Harley-Davidson 20W-50 motorcycle oil or equivalent (check manual for specific part numbers and API specifications)
Engine Oil Capacity:
Approx. 3 quarts (2.8 liters) with filter
Transmission Fluid:
SAE 80W-90 gear oil or Harley-Davidson transmission fluid
Primary Drive Fluid:
Harley-Davidson primary chaincase lubricant or SAE 20W-50 motorcycle oil
Brake Fluid:
DOT 4 hydraulic brake fluid
Primary Chain Tensioner:
The automatic primary chain tensioner on early Evo models (pre-2007) can wear out, leading to noise and potential damage. Manual adjustment or replacement with an upgraded tensioner is recommended.
Carburetor Tuning:
The Keihin CV carburetor may require periodic adjustment for optimal performance and fuel economy, especially with modifications or altitude changes.
Oil Leaks:
Common on older V-twins, often from gaskets, seals, or O-rings, requiring regular inspection and potential replacement.
Cam Chain Tensioners:
While not as common as primary tensioner issues, internal cam chain tensioners can wear on some Evo engines, often indicated by ticking noises. This manual will detail inspection and replacement procedures.
Legacy:
Harley-Davidson, founded in 1903, is an iconic American motorcycle manufacturer renowned for its V-twin engines and distinctive styling.
Softail Platform:
The Softail chassis, introduced in 1983, features concealed rear shock absorbers, giving the appearance of a hardtail frame while providing modern suspension benefits.
Introduction Year:
The FLSTF Softail Fat Boy was introduced in 1990, inspired by the Harley-Davidson Fat Man of the 1940s and made famous by its role in the movie 'Terminator 2: Judgment Day'.
Major Updates 1990-1999:
Over this period, the FLSTF received minor updates, including potential refinements to the engine (e.g., ignition system improvements), carburetor tuning, and cosmetic changes. The core design remained consistent.
Cultural Impact:
The Fat Boy's iconic status, partly cemented by its appearance in 'Terminator 2', has led to significant cultural recognition and enduring appeal.
Reliability:
Generally considered reliable with proper maintenance; the Evo engine is known for its durability.
Manual Quality:
This manual is designed to meet professional service standards, providing the detailed information required for authorized Harley-Davidson service centers.
