Factory Workshop SpecificationsPlatform Gen: 1990–2026

2015 Harley-Davidson Fat Boy / Fat Boy 114 (FLSTF / FLFB / FLFBS) Specifications & Consumables

Official workshop technical reference: fluid capacities, spark plug codes, drive chain specs, and tire inflation pressures.

Technical PassportOEM VERIFIED

Engine

1868cc

Cooling

Air / Oil-Cooled with Dual Internal Counterbalancers

Final Drive

Belt Drive

Engine Oil

4.70 L (5.00 US qt)

Spark Plug

H-D 6R10 / 6R12

Front Tire

160/60R18 70V

Gen 1990–2026

Factory Platform Compatibility: All workshop fluid capacities, maintenance milestones, torque specifications, and consumables on this specification sheet are factory-identical across model years 1990 through 2026.

Select Model Year:(Active: 2015)
37 Production Years (1990–2026)

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026

Engineering Subsystem Workbenches & Calculators

Dedicated deep-dive diagnostic tools, torque matrices, wiring pinouts, and calculators tailored for 2015 Harley-Davidson Fat Boy / Fat Boy 114 (FLSTF / FLFB / FLFBS).

10 Dedicated Engineering Spoke Pages

Subsystem Guide/torques

Fastener Torques

Engine drain plug, axle spindles, caliper mounts, triple clamp pinch bolts & thread lubrication derating guide.

Open Dedicated Workbench →

Subsystem Guide/fluids

Fluids & Capacities

Oil: 4.70 L (5.00 US qt) • Coolant: Not Applicable (Air / Oil Cooled) • Brake: N/A

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Subsystem Guide/fuses-relays

Fuses & Relays

Main: N/A • Location: N/A

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Subsystem Guide/compression

Compression & Leakdown

Ratio: N/A

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Subsystem Guide/valves

Valve Clearances

Intake: N/A mm • Exhaust: N/A mm

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Subsystem Guide/fuel-delivery

Fuel Delivery & TB Sync

Idle: N/A • Rail Pressure: N/A • Vacuum: N/A

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Subsystem Guide/electrical

Charging & Battery

Battery: YTX20HL-BS / H-D 65989-97E

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Subsystem Guide/tires

Tires & Gearing

Front: 160/60R18 70V • Rear: 240/40R18 79V

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Subsystem Guide/suspension

Suspension & Sag

Front Travel: N/A • Rear Travel: N/A

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Subsystem Guide/maintenance

Maintenance Schedule

Oil: N/A • Valves: N/A • Plugs: N/A

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Fluids & Service Capacities

Shop Fluids →

Engine Oil (Drain & Filter Change)4.70 L (5.00 US qt)

Engine Oil (Drain Only)N/A

Recommended Oil ViscosityH-D Screamin' Eagle SYN3 20W-50 Full Synthetic or Genuine H-D 360 20W-50

Coolant System CapacityNot Applicable (Air / Oil Cooled)

Brake Fluid StandardNot Available

Drivetrain, Chain & Gearing

Gearing Calculator →Shop Chains & Sprockets →

Drive Chain PitchBelt Drive

Chain Link Count133-Tooth Carbon-Fiber Reinforced (24mm width)

Front Sprocket TeethN/A

Rear Sprocket TeethN/A

Final Drive ConfigurationCarbon Belt Drive

Ignition & Electrical Specifications

Shop Plugs & Batteries →

OEM Spark Plug Part NumberH-D 6R10 / 6R12

Electrode Spark Plug Gap0.8–0.9 mm (0.031–0.035 in)

OEM Battery Reference CodeYTX20HL-BS / H-D 65989-97E

Battery Output & RatingNot Available

Spark Plug Inspection IntervalN/A

Wheels, Tires & Inflation Pressures

Matched 2-Tire Sets →

Front Tire Dimensions160/60R18 70V

Cold Front Inflation PressureN/A

Rear Tire Dimensions240/40R18 79V

Cold Rear Inflation PressureN/A

OEM Wheel Rim Widths (F / R)3.50" / 5.50"

Verified OEM Wheel Fitment: 160/60-18 (F) + 240/40-18 (R)

Shop In-Stock Matched Pairs→

Official NHTSA Safety Recalls & Technical Bulletins

3 Active Campaigns

U.S. Department of Transportation compliance database (Title 49 U.S.C. Chapter 301).

Verify VIN on NHTSA.gov

The U.S. National Highway Traffic Safety Administration reports 3 safety recall campaigns associated with this platform. Independent repair shops and riders should confirm that authorized dealership warranty remedies have been applied.

NHTSA #25V375000SUSPENSION:REAR:SHOCK ABSORBER

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Defect Description

Harley Safety Recall 0188: 2018–2024 Softail rear shock pre-load adjuster mounting tab can fracture under vibration, potentially allowing adjuster to contact rear tire.

Safety Hazard / Consequence

Contact between adjuster body and rear tire can cause tire damage, sudden loss of tire pressure, and loss of vehicle control.

Factory Remedy & Repair Action

Dealers install a reinforced retention bracket kit free of charge.

NHTSA #23V591000SUSPENSION:REAR:SHOCK ABSORBER

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NHTSA #18V734000POWER TRAIN:CLUTCH ASSEMBLY

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OEM Workshop Archives

Official Factory Service Bulletins & Field Updates

2 Documented Bulletins

Bulletin #HD-0181Safety Recall Bulletin 0181 & 0182 / NHTSA 23V-591: Softail Rear Shock Absorber Pre-Load Fastener Rear Tire Contact

Source: RCLRPT-23V591-6615.PDF

Mandated Torques:Torque: 12–15 N·m (106–133 in-lb) (Pre-load Adjuster Bracket Mounting Screw)Torque: 95–108 N·m (70–80 lb-ft) (Upper & Lower Shock Eye Mount Bolts)Torque: 136–149 N·m (100–110 lb-ft) (Rear Axle Cone Nut)

Consumable Specs:Loctite 243 Medium Strength Blue ThreadlockerIsopropyl Alcohol Surface Cleaner

Genuine Part Numbers:102008499150010454000142

Recalls 0181 & 0188 • NHTSA 23V-591 & 25V-375

Harley-Davidson Softail Mono-Shock Pre-Load Adjuster & Tire Clearance Architecture

Fast adjuster bracket reinforcement, tire clearance inspection (≥ 10 mm), and 95–108 N·m shock mounting torques.

Shock Mounting Bolts95–108 N·m (70–80 lb-ft)

Adjuster Bracket Screw12–15 N·m (106–133 in-lb)

Chemical ThreadlockerLoctite 243 (Medium Blue)

Dynamic Tire Clearance≥ 10.0 mm (0.39 in)

Bulletin #HD-TSB-21-04Technical Service Bulletin TSB-21-04: Fat Boy Solid Lakester Wheel Hub, 240mm Rear Tire & Pulley Torques

Source: H-D_TSB_21-04_Lakester_Hub.pdf

Mandated Torques:Torque: 75–88 N·m (55–65 lb-ft) + 45°–50° Turn (Rear Driven Pulley Bolts - Loctite 262 Red)Torque: 41–47 N·m (30–35 lb-ft) (Front & Rear Brake Rotor Torx Screws - Loctite 243 Blue)Torque: 136–149 N·m (100–110 lb-ft) (Rear Axle Cone Washer & Nut)Torque: 102 N·m (75 lb-ft) (Front Axle)Torque: 24–27 N·m (18–20 lb-ft) (Front Axle Pinch Bolts)

Consumable Specs:Loctite 262 High-Strength Red Threadlocker (Pulley Bolts)Loctite 243 Medium-Strength Blue Threadlocker (Rotor Screws)Anti-Seize Lubricant (Axle Shafts)

Genuine Part Numbers:410003913700021441500147

Fat Boy Icon • Lakester Solid Disc Driveline

Harley-Davidson Fat Boy Solid Lakester Wheel & 240mm Rear Driveline Hub Assembly

Cast solid disc wheel torques, 240/40R18 rear tire specs, 136–149 N·m rear axle, and driven pulley angle torque.

Rear Axle Nut136–149 N·m (100–110 lb-ft)

Driven Pulley Bolts75–88 N·m + 45°–50° Turn

Brake Rotor Screws41–47 N·m (30–35 lb-ft)

Front Axle Nut102 N·m (75 lb-ft)

1-Click Factory Service KitOEM Spec Fluid Capacities Matched

Workshop Maintenance Kit & Factory Fluids

Authentic factory-grade motor oil, oil filter, and high-temp brake fluid matched precisely to 2015 Harley-Davidson Fat Boy / Fat Boy 114 (FLSTF / FLFB / FLFBS) capacities.

Full Kit Subtotal

$47.80

20W-50 Heavy-Duty Synthetic

Silkolene Comp 4 4T Oil 20W-50 (1 Quart)

1-Quart Bottles (x4 Included)

Matches factory 20W-50 spec (Oil spec: 4.70 L (5.00 US qt))

Item Price

$47.80($11.95 ea)

Factory OEM Spark Plug Spec

H-D 6R10 / 6R12

Gap: 0.8–0.9 mm (0.031–0.035 in)

Inspection milestone: Not Available. Exact factory part specification.

Authentic OEM Reference

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Complete Workshop Maintenance Package3 Essential Service Items

Includes 20W-50 Heavy-Duty Synthetic engine oil (1-Quart Bottles (x4 Included)), high-flow filter & DOT 4 fluid.

Kit Total

$47.80

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