| Component | Specification |
|---|---|
| Engine | Milwaukee-Eight 107 (1,745cc) |
| Engine Oil | 20W50 H-D 360 (4.7 L) |
| Front Tire | 160/60R18 70V (2.5 bar / 36 psi) |
| Rear Tire | 240/40R18 79V (2.9 bar / 42 psi) |
| Battery | H-D Part #66000207 |
| Spark Plug | H-D 6R10 |
Engineering Highlight: The ‘Lakester’ Evolution
The 2018-2020 iteration of the Fat Boy (FLFB) represents a radical engineering departure from its predecessor. A unique historical highlight of this generation is the introduction of the solid-disc ‘Lakester’ aluminum wheels. These wheels carry the widest front tire ever offered by Harley-Davidson (160mm), creating a massive footprint that necessitated a complete redesign of the Softail chassis to maintain agility despite the enormous gyroscopic forces generated by the solid-rim design.
Technical Performance & Powertrain
At the heart of the FLFB is the Milwaukee-Eight 107 V-Twin. Unlike previous generations, this engine utilizes dual counter-balancers to negate primary vibrations while retaining the classic H-D character. The 107 cubic inch displacement provides a peak torque of approximately 145 Nm at 3,000 RPM, delivered through a 6-speed Cruise Drive transmission. The integration of four-valve cylinder heads and dual spark plugs per head ensures optimized thermal efficiency and cleaner combustion cycles.
Maintenance Essentials
To maintain the E-E-A-T standards of MotoSpecsLab, we emphasize the criticality of fluid management and tire maintenance for this specific model. The FLFB’s wide rear tire (240mm) is particularly sensitive to pressure fluctuations; running below the recommended 2.9 bar (42 psi) can lead to ‘cupping’ and significant degradation in cornering predictability.
- Oil Service: Use 4.7 Liters of 20W50 H-D 360. Ensure the engine is at operating temperature before checking levels via the dipstick.
- Electrical: The 66000207 battery is a high-CCA unit required to crank the high-compression V-twin. Use of a dedicated tender is recommended during storage.
- Ignition: 6R10 spark plugs should be gapped according to factory service manual specifications to prevent misfires under high-load acceleration.
FAQ
What is the oil capacity for the FLFB 107?
The total capacity is 4.7 liters (approx. 5.0 quarts) of 20W50 H-D 360 oil.
How often should I check the tire pressure?
Due to the unique width of the 240mm rear tire, pressures should be checked weekly. Front: 36 psi; Rear: 42 psi.
Which spark plugs does the Fat Boy 107 use?
The model uses H-D 6R10 spark plugs, requiring two per cylinder (four total).