| Component | Specification |
|---|---|
| Engine | Milwaukee-Eight 117 V-Twin |
| Oil Type | SAE 20W50 (4.7 L) |
| Front Tire | 110/90B19 62H (36 psi) |
| Rear Tire | 180/70B16 77H (42 psi) |
| Spark Plugs | HD-6R10 |
| Battery | 66000207 |
The Harley-Davidson Low Rider S (FXLRS) represents a pivotal engineering shift in the Softail lineup. While the ‘S’ designation traditionally denoted cosmetic upgrades, the 2022-2025 iteration utilizes the Milwaukee-Eight 117 powertrain—a displacement previously exclusive to the elite Custom Vehicle Operations (CVO) models. This factory-installed performance marks the first time a standard production Softail has achieved this level of torque-to-weight ratio from the assembly line.
Engineering Analysis: The 117 CUI Powerhouse
The heart of the FXLRS/25 is the 1,923cc (117 cubic inch) engine, featuring precision oil/air cooling and a Heavy Breather intake. This setup demands rigorous thermal management, necessitating the use of 4.7 liters of SAE 20W50 oil. At MotoSpecsLab, we recommend high-viscosity synthetic fluids to maintain shear stability during the high-torque output typical of the 117 platform.
Chassis and Handling Dynamics
The Low Rider S utilizes a 43mm inverted front fork and a hidden, nitrogen-charged rear monoshock with hydraulic preload adjustment. To maintain the ‘West Coast’ handling profile, tire pressures are critical. The 19-inch front wheel requires 36 psi (2.5 bar), while the 16-inch rear requires 42 psi (2.9 bar) to handle the 125 ft-lb of torque without compromising the sidewall integrity of the 180mm rear tire.
Maintenance Essentials
- Electrical: The model utilizes the high-capacity 66000207 battery. Given the high compression of the 117 engine, maintaining a full charge is vital for starter longevity.
- Ignition: The HD-6R10 plugs should be inspected every 5,000 miles to ensure optimal combustion and prevent carbon fouling in the large-bore cylinders.
- Drive Train: Regular belt tension checks are mandatory, as the 117’s torque can accelerate belt stretch during the break-in period.
Technical Conclusion
The FXLRS/25 is more than a cruiser; it is a performance-oriented machine that requires precision maintenance. By adhering to the 4.7L oil capacity and specific tire pressures, owners can ensure the Milwaukee-Eight 117 delivers its legendary power reliably.