| Component | Specification |
|---|---|
| Engine | Milwaukee-Eight 117 V-Twin (1,923cc) |
| Oil Specification | 20W50 (H-D 360 or SYN3) |
| Oil Capacity | 4.73 Liters (5.0 US qt) |
| Front Tire | 130/60B19 61H (2.48 bar / 36 psi) |
| Rear Tire | 180/55B18 80H (2.90 bar / 42 psi) |
| Spark Plugs | HD-6R10 |
| Battery Part No. | 66000641 |
A significant engineering milestone for the FLHXU/25 platform is the standardization of the 117 cubic inch (1,923cc) Milwaukee-Eight powertrain, a displacement previously reserved strictly for the premium CVO (Custom Vehicle Operations) lineup. This transition introduces high-flow exhaust architecture and precision oil cooling to the mainstream touring chassis, offering a 10% increase in torque over the preceding 114 engine variants.
Engineering Overview
The Street Glide Ultra (FLHXU/25) represents the pinnacle of Grand American Touring. The 117 cubic inch engine features a high-performance camshaft and a heavy-breather intake that optimizes volumetric efficiency. From a technical standpoint, the integration of the Skyline™ OS infotainment system alongside the mechanical refinements indicates a shift toward a fully digital-mechanical hybrid interface, enhancing rider feedback and engine monitoring.
Maintenance Guide & Technical Specs
Lubrication System
The Milwaukee-Eight 117 utilizes a dry-sump system. For the 2024-2025 models, the total refill capacity is 4.73 liters. MotoSpecsLab recommends the use of H-D 360 Mineral 20W50 for standard break-in periods, while SYN3 Full Synthetic is preferred for high-temperature stability and extended service intervals.
Chassis and Contact Patch
The FLHXU/25 demands precise tire pressure management to maintain its high-speed stability and cornering clearance. The front 19-inch wheel requires 36 psi (2.48 bar), while the 18-inch rear wheel, which bears the brunt of the luggage and passenger load, must be maintained at 42 psi (2.90 bar). Failure to maintain these pressures can lead to uneven cupping of the Dunlop® Multi-Tread tires.
Electrical and Ignition
The ignition system utilizes HD-6R10 spark plugs. Given the high-compression nature of the 117 engine, electrode gap inspection is critical every 8,000 km. The electrical system is anchored by the 66000641 battery, which provides the necessary cold-cranking amps (CCA) to turn over the large-displacement V-twin in adverse conditions.
Editor’s Verdict
The Harley-Davidson Street Glide Ultra 117 (FLHXU/25) is more than a cosmetic update; it is a mechanical evolution. By bringing the 117 cui engine to the standard Ultra configuration, Harley-Davidson has set a new benchmark for touring performance. Proper adherence to the 4.73L oil capacity and specific tire pressures listed above is mandatory for preserving the machine’s sophisticated handling dynamics.