| Component | Specification |
|---|---|
| Model Years | 2016-2017 |
| Engine | Screamin’ Eagle Twin Cam 110B |
| Oil Type | 20W50 (SYN3 Full Synthetic) |
| Oil Capacity | 2.8 Liters |
| Front Tire | 140/75R17 67V |
| Rear Tire | 200/55R17 78V |
| Tire Pressure (F/R) | 36 psi / 42 psi |
| Spark Plug | H-D 6R12 |
| Battery Part Number | 66000207 |
Engineering Highlight: The Fat Boy S (FLSTFBS) represents a pivotal moment in Softail history as the first factory-production model to democratize the Screamin’ Eagle Twin Cam 110B engine. Previously a CVO-exclusive powerhouse, this counterbalanced 1,801cc V-Twin was integrated into the Fat Boy S to create the ultimate ‘Dark Custom’ cruiser, delivering 108 lb-ft of peak torque directly to the pavement.
Performance Analysis: The 110B Powerplant
At the heart of the FLSTFBS is the air-cooled, Twin Cam 110B engine. Unlike the standard rubber-mounted touring engines, the ‘B’ designation signifies a counterbalanced design, allowing the high-displacement motor to be rigid-mounted within the Softail frame. This results in a visceral connection between the rider and the machine without the excessive vibration typically associated with such high-torque outputs.
Maintenance & Lubrication Guide
To maintain the tight tolerances of the Screamin’ Eagle components, MotoSpecsLab recommends adhering strictly to the full synthetic 20W50 oil specification. The 2.8-liter oil capacity (with filter change) is critical for heat dissipation in this large-bore air-cooled engine. Using a high-quality synthetic like SYN3 ensures the hydraulic lifters and chain tensioners remain lubricated under the high operating temperatures common to the 110B.
Tires and Chassis Handling
The Fat Boy S is defined by its massive 200mm rear tire. While providing an iconic silhouette, it requires precise pressure management to ensure predictable cornering. Maintaining 42 psi in the rear is essential to prevent ‘cupping’ and to support the weight of the steel-heavy chassis. The front 140mm tire should be kept at 36 psi to provide a stable contact patch during heavy braking, which is handled by the standard ABS-equipped Brembo-derived calipers.
Technical FAQ
Which spark plugs are best for the FLSTFBS?
We recommend the Harley-Davidson 6R12 plugs. These are specifically gapped and heat-ranged for the high-compression environment of the Twin Cam 110B engine.
What battery is required?
The FLSTFBS utilizes the high-crank capacity battery part number 66000207. Given the high compression of the 110-cubic-inch motor, maintaining a healthy battery with high Cold Cranking Amps (CCA) is vital for reliable starting.