🏷️ Basic Information

Make:

Harley-Davidson

Model:

FLSTF Fat Boy

Year:

2015

Model Code:

FLSTF

Vin Character Vehicle Section Identification:

The 17th character of the VIN denotes the model year.

👋 Introduction

Segment:

Cruiser Motorcycle

Target Audience:

Harley-Davidson owners, enthusiasts, and independent repair shops specializing in Harley-Davidson motorcycles.

Key Competitors 2015:

Indian Chief Vintage, Victory Kingpin, Honda Shadow series, Yamaha Bolt, Kawasaki Vulcan series.

Model Identity:

The FLSTF Fat Boy is an iconic cruiser known for its distinctive styling, fat tires, chrome accents, and comfortable riding position, representing a classic American motorcycle aesthetic.

Manual Value Proposition:

Provides the technical knowledge necessary for owners to perform a wide range of maintenance and repair tasks, thereby saving on dealership service costs and enhancing ownership experience.

📋 Manual Details

Systems Covered:

Engine, Fuel System, Ignition System, Drivetrain, Transmission, Clutch, Chassis, Suspension, Brakes, Electrical System, Lighting, Instruments, Bodywork, Frame, Wheels, Tires, Body Panels, Fairings, Maintenance, Troubleshooting, Diagnostics, Specifications, Torque Values, Wiring Diagrams, Service Procedures, Overhaul Procedures, Tune-up Procedures, Parts Information, Fluid Recommendations, Lubrication, Cooling System (if applicable, though typically air-cooled for this model).

Estimated Page Count:

500-800 pages (typical for a comprehensive workshop manual of this nature)

Manual Type:

Workshop Service Repair Manual

Language:

English

Format:

Downloadable Digital File (PDF)

📖 Manual Coverage

Engine Mechanical:

Detailed disassembly, inspection, assembly, and troubleshooting of Twin Cam 103 engine components including cylinders, pistons, connecting rods, crankshaft, camshafts, valves, lifters, pushrods, oil pump, and timing components. Includes bore, hone, and assembly specifications.

Fuel System:

Comprehensive coverage of Electronic Sequential Port Fuel Injection (ESPFI), fuel pump, injectors, throttle body, fuel pressure regulator, and fuel lines. Includes diagnostics and component testing.

Ignition System:

Diagnosis and repair of the ignition system, including spark plugs, ignition coils, crank position sensors, and ECU (Engine Control Unit) related functions.

Drivetrain Transmission:

Complete service and repair procedures for the 6-speed Cruise Drive transmission, including clutch operation, primary drive, gear selection, internal components, and lubrication. Includes transmission fluid specifications and change intervals.

Chassis Suspension Brakes:

Detailed repair and maintenance of front and rear suspension (telescopic forks, shock absorbers), braking systems (hydraulic disc brakes front and rear), wheel bearings, steering head bearings, and all related components. Includes brake fluid specifications and bleeding procedures.

Electrical System:

Extensive coverage of the electrical system, including battery, charging system (alternator, regulator), starter motor, lighting circuits (headlight, taillight, turn signals), horn, instruments, switches, fuses, relays, and wiring diagrams for all circuits. Includes diagnostic procedures for electrical faults.

Bodywork Frame:

Information on frame inspection, body panel removal and installation, fenders, fuel tank, seat, handlebars, and any cosmetic components. Includes torque specifications for mounting hardware.

Preventative Maintenance:

Routine maintenance tasks such as oil changes, filter replacements, spark plug service, brake checks, tire pressure checks, and lubrication points.

Troubleshooting Diagnostics:

Systematic troubleshooting guides for common issues, diagnostic flowcharts, and error code interpretation (if applicable).

Rebuild Overhaul:

Complete procedures for engine, transmission, and suspension component rebuilds, including detailed specifications and tolerances.

Component Replacement:

Step-by-step instructions for replacing all major and minor components.

Wiring Diagrams:

Detailed, color-coded wiring diagrams for all electrical systems, aiding in fault diagnosis and repair.

Depth Of Coverage:

Comprehensive, covering everything from basic fluid changes and adjustments to full engine and transmission rebuilds, electrical system diagnostics, and frame-level repairs. Suitable for both DIY enthusiasts and professional technicians.

📊 Manual Specifications

File Format:

PDF

Print Quality:

High-resolution, ensuring clarity of text, diagrams, and images. Searchable text for easy navigation.

Binding Type:

N/A (Downloadable digital format)

Paper Type:

N/A (Downloadable digital format)

⚙️ Engine Specifications

Engine Type:

Air-cooled, Twin Cam 103™ V-Twin

Displacement:

103 cu in (1690 cc)

Bore X Stroke:

3.875 in x 4.375 in (98.4 mm x 111.1 mm)

Compression Ratio:

9.6:1

Valve Train:

Overhead Valves (OHV), 2 valves per cylinder, pushrod actuated

Peak Torque Estimated:

Approximately 101 ft-lb (137 Nm) @ 3250 RPM

Fuel Delivery:

Electronic Sequential Port Fuel Injection (ESPFI)

Fuel Type:

Premium Unleaded Gasoline, minimum 91 octane

Oil Type Engine:

Harley-Davidson SYN3 Synthetic Motorcycle Oil (or equivalent API SG, JASO FD/FE approved synthetic oil)

Oil Capacity Engine W Filter:

4.0 US quarts (3.8 Liters)

🔧 Transmission

Transmission Type:

6-speed Cruise Drive®

Primary Drive:

Chain, 34/46 ratio

Final Drive:

Belt, 32/66 ratio

Clutch Type:

Hydraulic, 9-plate, wet clutch

Transmission Fluid Type:

Harley-Davidson Formula+ (or equivalent SAE 50 API GL-1 gear oil)

Transmission Fluid Capacity:

2.7 US quarts (2.6 Liters)

📐 Dimensions

Length:

97.4 in (2474 mm)

Width:

36.1 in (917 mm)

Height:

49.3 in (1252 mm)

Wheelbase:

64.2 in (1630 mm)

Ground Clearance:

4.8 in (122 mm)

Seat Height Laden:

26.1 in (663 mm)

Dry Weight:

697 lb (316 kg)

Gross Vehicle Weight Rating Gvwr:

1160 lb (526 kg)

Fuel Capacity:

5.0 US gallons (18.9 Liters)

Front Tire:

130/90B16 67H BW

Rear Tire:

150/80B16 77H BW

Wheel Type:

Cast aluminum, chrome finish, solid disc wheels

🛡️ Safety Features

Crash Test Ratings:

Motorcycles are generally not subject to the same formal crash test rating systems as automobiles. Safety is determined by design and rider skill.

Braking System:

Hydraulic disc brakes, front and rear. Anti-lock Braking System (ABS) may be an optional feature depending on specific build.

Lighting:

Halogen headlamp, LED taillight, amber incandescent front and rear turn signals.

Frame Construction:

Steel, rigid frame, mild steel. Powder-coated or painted finish.

💡 Technology Features

Audio System:

Factory audio system (if equipped) typically includes AM/FM radio, CD/MP3 player, and handlebar-mounted controls. Often integrated with a handlebar-mounted display.

Display Type:

Analog speedometer with integrated LCD screen displaying odometer, trip meter, clock, gear indicator, and fuel level.

ABS Availability:

Anti-lock Braking System (ABS) was an available option for the 2015 FLSTF Fat Boy.

Phone Integration:

No native smartphone integration or Bluetooth connectivity on base models. Aftermarket solutions may be available.

🔧 Maintenance

Initial Service Mileage:

1,000 miles (1,600 km)

Subsequent Service Interval Engine Oil:

Every 5,000 miles (8,000 km) or annually, whichever comes first.

Subsequent Service Interval Transmission Clutch:

Every 10,000 miles (16,000 km) or every two years.

Primary Chain Case Fluid:

Harley-Davidson Formula+ or equivalent SAE 50 API GL-1 gear oil.

Brake Fluid:

DOT 4 (refer to manual for specific recommendations regarding ABS compatibility)

Fork Oil Type:

Refer to manual for specific viscosity (e.g., Spectro Heavy Duty, Harley-Davidson fork oil).

Cam Chain Tensioner Wear:

While later Twin Cam engines have updated hydraulic tensioners, early versions could experience wear. The 2015 model uses hydraulic tensioners, which are more robust but still require inspection and potential replacement as part of a comprehensive service.

Oil Leaks:

Common areas for oil leaks include primary cover, transmission side cover, and rocker boxes due to gasket aging or improper installation. The manual provides procedures for sealing and gasket replacement.

Charging System Issues:

Less common on this generation, but stator and voltage regulator failures can occur. The manual covers diagnosis and testing of these components.

📚 Vehicle History

Harley Davidson Legacy:

Founded in 1903, Harley-Davidson is the oldest American motorcycle manufacturer and a global icon of freedom and the open road. Known for its V-twin engines and distinctive styling.

Fat Boy Introduction:

The Fat Boy (FLSTF) was first introduced in 1990, heavily influenced by the styling of the 1949 Hydra-Glide. It quickly became one of Harley-Davidson's most recognizable and popular models.

2015 Model Updates:

For 2015, the Fat Boy continued with the Twin Cam 103 engine and Cruise Drive transmission, benefiting from the refinements made to the Softail platform. Key features included a lower seat height, wide fork, and large headlight nacelle.

Manufacturing Location:

United States (primarily York, Pennsylvania, and Milwaukee, Wisconsin)

🏆 Awards & Recognition

Model Reputation:

Consistently recognized as a benchmark in the cruiser motorcycle segment for its iconic styling, comfort, and V-twin performance.

Owner Satisfaction:

Generally high owner satisfaction, particularly for riders who appreciate the classic styling and relaxed riding experience. Specific awards are less common for individual model years compared to overall brand or segment recognition.