| Component | Specification |
|---|---|
| Engine Model | Revolution Max 1250T (Liquid-cooled V-Twin) |
| Production Years | 2021 – Present |
| Engine Oil | Screamin’ Eagle SYN3 Full Synthetic 15W-50 (4.5 L) |
| Front Tire | 160/70 TR 17 73V (36 psi / 2.5 bar) |
| Rear Tire | 180/70 R 16 77V (42 psi / 2.9 bar) |
| Spark Plugs | HD-6R10 (Gap: 0.8–0.9 mm) |
| Battery Part No. | 66000300 |
Engineering Highlight: The Departure from Pushrods
The Harley-Davidson Sportster S (RH1250S) represents the most significant engineering pivot in the model line’s 65-year history. Unlike its predecessors, which relied on the iconic air-cooled Evolution engine, the RH1250S utilizes the Revolution Max 1250T. This engine is a structural component of the chassis, eliminating the traditional frame to reduce weight and increase rigidity. Notably, it features double overhead cams (DOHC) and independent variable valve timing (VVT) on both the intake and exhaust, a level of sophistication previously reserved for high-performance European sportbikes.
Technical Performance Analysis
The “T” in 1250T stands for torque. While the Pan America’s version of this engine focuses on top-end horsepower, the Sportster S is tuned to deliver a massive surge of torque in the low and mid-range. With 121 horsepower and 94 ft-lb of torque, the power-to-weight ratio is unprecedented for the Sportster family. The use of hydraulic valve lash adjusters ensures that the valvetrain remains maintenance-free, a major advantage for long-distance owners.
Maintenance Guide & Technical Specifications
Lubrication System
The RH1250S utilizes a dry-sump lubrication system. For optimal performance and thermal stability in the high-revving Revolution Max engine, MotoSpecsLab recommends Screamin’ Eagle SYN3 Full Synthetic 15W-50. The total refill capacity with a filter change is 4.5 Liters. Proper oil level checks should be performed with the bike upright and the engine at operating temperature.
Tires and Contact Patch
The Sportster S features an aggressive tire setup with a wide 160mm front tire. Maintaining precise pressures is critical for handling agility:
- Front: 2.5 bar (36 psi) for the 160/70 TR 17 73V.
- Rear: 2.9 bar (42 psi) for the 180/70 R 16 77V.
Ignition and Electrical
The high-compression V-twin requires a precise spark. Use HD-6R10 plugs with a gap set strictly between 0.8 and 0.9 mm. The electrical system is supported by the 66000300 battery, which should be kept on a tender during storage due to the bike’s advanced IMU and infotainment parasitic draw.
Frequently Asked Questions
What is the recommended service interval for the Sportster S?
The first break-in service is required at 1,000 miles (1,600 km), followed by standard service intervals every 5,000 miles (8,000 km).
Does the RH1250S require valve adjustments?
No. Thanks to the hydraulic lifters in the Revolution Max 1250T engine, manual valve clearance adjustments are not required, significantly lowering long-term maintenance costs.