Market Segment:
Cruiser Motorcycle, Iconic American Styling
Key Competitors:
Other Harley-Davidson Softail models, Indian Chief models, select Japanese cruisers
Model Identity:
Renowned for its distinctive wide front tire, chrome accents, and classic Harley-Davidson cruiser aesthetics
Manual Purpose:
To provide owners and technicians with the authoritative information needed for accurate maintenance and repair, ensuring optimal performance and longevity of the 2015 Softail Fat Boy.
Engine:
Full overhaul, diagnostics, tuning, specific component repair (e.g., cylinders, pistons, crankshaft, camshafts, valve train)
Fuel System:
Fuel injection system (EFI), throttle body, injectors, fuel pump, fuel lines, pressure testing
Ignition System:
Ignition modules, spark plugs, wiring, coil diagnostics
Transmission:
Clutch operation, primary drive, transmission case, gears, shift mechanisms, lubrication
Drivetrain:
Final drive belt inspection, tensioning, replacement; rear wheel axle and bearings
Brakes:
Front and rear brake systems, hydraulic lines, master cylinders, calipers, rotors, bleeding procedures
Suspension:
Front fork (telescopic), rear shock absorbers, service, adjustment, and replacement
Electrical System:
Battery, charging system (alternator, regulator), lighting, starter motor, wiring diagrams, diagnostic codes (DTCs)
Chassis And Frame:
Frame inspection, swingarm, steering head bearings, wheel bearings
Bodywork And Trim:
Fenders, fuel tank, seat, handlebars, controls, cosmetic components
Wheels And Tires:
Wheel removal and installation, tire inspection, replacement, and pressure
Maintenance Tasks:
Oil changes, filter replacements, spark plug service, air filter cleaning/replacement, brake fluid flush, belt inspection and adjustment
Troubleshooting:
System-specific diagnostic procedures, common fault identification and rectification, symptom-based troubleshooting guides
Repair Procedures:
Step-by-step instructions for component removal, overhaul, repair, and reassembly
Specifications And Tolerances:
Torque values, clearances, fluid capacities, diagnostic parameters
Wiring Diagrams:
Detailed electrical schematics for all systems
Depth Of Coverage:
Comprehensive: Covers basic maintenance to complete engine rebuilds and complex electrical diagnostics
Engine Type:
Air-cooled, Twin Cam 103B™
Displacement:
1690 cc (103 cubic inches)
Bore X Stroke:
3.875 in. x 4.375 in. (98.4 mm x 111.1 mm)
Torque Peak:
Approx. 99 ft-lbs @ 3,250 RPM (134 Nm @ 3250 rpm)
Horsepower Estimate:
Typically in the range of 75-80 HP (Actual figures vary, manual will have precise dynamometer data if available).
Fuel Delivery:
Electronic Sequential Port Fuel Injection (ESPFI)
Fuel Type:
Premium unleaded gasoline, minimum 91 octane
Oil Type:
Harley-Davidson Genuine V-Twin 20W-50 Synthetic (or equivalent meeting Harley-Davidson specification)
Oil Capacity:
4.2 US qt (4.0 L) with filter change
Type:
6-speed Cruise Drive®
Clutch Type:
Hydraulically actuated, multiplate wet clutch
Primary Drive:
Plated, heavy-duty, and offset chain
Final Drive:
Belt, 25mm wide, 140-tooth, 51T/70T sprockets
Transmission Oil Type:
Harley-Davidson Formula + Transmission & Primary Chaincase Lubricant (or equivalent meeting Harley-Davidson specification)
Transmission Oil Capacity:
1.0 US qt (0.95 L)
Initial 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. (Note: Manual will detail specific interval checks like oil changes, belt inspection, brake fluid.)
Primary Chaincase Lubricant:
Harley-Davidson Formula + Transmission & Primary Chaincase Lubricant or equivalent
Engine Oil:
Harley-Davidson Genuine V-Twin 20W-50 Synthetic or equivalent
Brake Fluid:
DOT 4 (refer to manual for specific Harley-Davidson approved P/N)
Fork Oil:
Viscosity and quantity specified in manual, often a specific grade of suspension fluid
Common Wear Items:
Clutch plates, brake pads, drive belt, wheel bearings, fork seals (typical for any motorcycle, manual will provide specific wear limits)
Potential Twin Cam Considerations:
While the Twin Cam 103 is robust, the manual will cover checks for compensator sprocket wear, cam chain tensioners, and potential oil leaks typical for this engine family.
Brand Legacy:
Harley-Davidson, founded in 1903, is an iconic American motorcycle manufacturer with a rich heritage in cruiser and touring motorcycle design.
Fat Boy Introduction:
The Fat Boy model, first introduced in 1990, is recognized for its styling cues from the pre-WWII Harley-Davidson designs, notably the FLs of the 1940s.
Production Period:
The 2015 model year represents a continuation of the Softail platform, featuring the Twin Cam 103 engine, a popular and refined powerplant for Harley-Davidson.
