Positioning:
The 2015 Fat Boy represents a modern interpretation of Harley-Davidson's iconic cruiser heritage, blending classic styling with contemporary engineering.
Competitors:
Competes with other large-displacement cruisers from brands like Indian Motorcycle, Victory Motorcycles (discontinued), and Japanese manufacturers offering similar styling.
Styling:
Iconic wide front tire, chrome accents, teardrop fuel tank, and broad handlebars.
Engine:
Harley-Davidson's air-cooled Twin Cam 103 V-twin engine, known for its torque and distinctive sound.
Ride Quality:
Comfortable riding position and smooth power delivery suitable for long-distance touring and cruising.
Value:
This service manual is an indispensable tool for owners and technicians looking to maintain, diagnose, and repair the 2015 FLSTF Fat Boy with factory-specified procedures and data.
Engine:
Engine disassembly, assembly, inspection, diagnosis, and repair for the Twin Cam 103 engine.
Fuel System:
Fuel injection system, fuel pump, injectors, throttle body, and fuel tank service.
Ignition System:
Ignition module, spark plugs, ignition coils, and troubleshooting.
Transmission:
6-speed Cruise Drive transmission service, including disassembly, assembly, and fluid changes.
Clutch:
Clutch operation, adjustment, and repair procedures.
Drive Train:
Final drive belt inspection, tensioning, and replacement.
Suspension:
Front fork (telescopic) and rear shock absorber maintenance, adjustment, and overhaul.
Brakes:
Brake system service, including hydraulic lines, master cylinders, calipers, pads, and bleeding procedures.
Electrical System:
Wiring diagrams, battery, charging system, starter, lighting, and electronic controls.
Chassis:
Frame inspection, steering head bearing service, and general chassis components.
Bodywork:
Fender removal and installation, fuel tank mounting, seat assembly, and other body panels.
Wheels Tires:
Wheel bearing service, tire inspection and replacement, and tire pressure recommendations.
Routine Maintenance:
Oil changes, filter replacements, chain/belt adjustments, lubrication, and general inspection.
Troubleshooting:
System-specific troubleshooting guides, diagnostic flowcharts, and common problem identification.
Engine Repair:
Complete engine rebuild procedures, including top-end and bottom-end overhauls.
Transmission Repair:
Transmission disassembly, inspection of gears and bearings, reassembly, and adjustment.
Electrical Diagnosis:
Diagnostic steps for electrical faults, including use of multimeters and test equipment.
Suspension Overhaul:
Fork seal replacement, fork oil changes, and rear shock absorber service.
Brake System Service:
Brake fluid flush, pad replacement, caliper service, and bleeding.
Component Replacement:
Detailed instructions for replacing various components like starters, alternators, fuel pumps, etc.
Depth:
Comprehensive, covering everything from basic adjustments to full engine and transmission overhauls.
Accuracy:
Factory-level accuracy and detail, essential for professional or advanced DIY mechanics.
Engine Type:
Air-cooled, Twin Cam 103, V-twin
Displacement:
1690 cc (103 cubic inches)
Bore X Stroke:
3.875 in. x 4.38 in. (98.4 mm x 111.3 mm)
Valve Train:
Pushrod-actuated, overhead valves with two valves per cylinder
Torque Peak:
Approximately 101 ft-lbs @ 3250 RPM (specified by Harley-Davidson for Twin Cam 103 in this configuration).
Horsepower Peak:
Not officially published by Harley-Davidson, but estimated to be around 75-80 HP.
Fuel Delivery:
Electronic Sequential Port Fuel Injection (ESPFI)
Fuel Type:
Premium unleaded gasoline, 91 octane (R+M)/2 minimum
Type:
6-speed Cruise Drive, constant mesh
Gear Ratios:
1st: 9.312, 2nd: 6.471, 3rd: 4.792, 4th: 3.874, 5th: 3.307, 6th: 2.790
Primary Drive:
Plated, heavy-duty, 35 mm silent chain; gear ratio 34/46
Final Drive:
Belt Drive, 25 mm wide, 70-tooth pulley; 32/46 ratio
Clutch:
Hydraulically actuated, 10-plate, wet clutch
Transmission Fluid:
Harley-Davidson Genuine Formula + Transmission & Primary Chaincase Lubricant
Transmission Fluid Capacity:
Approximately 1.0 L (1.1 US qt)
Crash Test Ratings:
N/A (Motorcycles are not subjected to automotive crash testing standards.)
Brakes:
Dual-action, front and rear, hydraulic disc brakes.
ABS:
Optional Anti-lock Braking System (ABS) available for this model year and configuration.
Lighting:
Halogen headlamp, LED taillight, and front/rear turn signals.
Frame Construction:
Steel frame and front fork designed for stability and handling.
First Service:
1,000 miles (1,600 km) or 6 months.
Subsequent Service:
Every 5,000 miles (8,000 km) or 12 months, whichever comes first.
Engine Oil Change:
Every 5,000 miles (8,000 km) or 12 months.
Transmission Primary Fluid Change:
Every 10,000 miles (16,000 km) or 24 months.
Engine Oil Type:
Harley-Davidson Genuine V-Twin 20W-50 Synthetic (or approved equivalent).
Engine Oil Capacity:
Approximately 3.7 U.S. quarts (3.5 L) with filter change.
Fork Oil Type:
Harley-Davidson Genuine front fork oil (refer to manual for specific viscosity based on rider preference and conditions).
Common Wear Items:
Clutch cable adjustment, wheel bearings, brake pads, and drive belt inspection.
Twin Cam Considerations:
While generally robust, early Twin Cam engines (prior to some internal updates) had potential for cam chain tensioner wear; later models like the 2015 generally improved in this area.
Heritage:
Harley-Davidson, founded in 1903, is an iconic American motorcycle manufacturer renowned for its cruiser and touring motorcycles.
Fat Boy Origin:
The Fat Boy was first introduced in 1990, quickly becoming a cultural icon, most famously in the film 'Terminator 2: Judgment Day'.
Twin Cam Era:
The 2015 model features the evolution of the Twin Cam engine platform, which replaced the Evolution Big Twin in 1999.
Manufacturing Location:
Primarily manufactured in the United States (e.g., York, Pennsylvania; Kansas City, Missouri).
