| Specification | Data |
|---|---|
| Engine | Milwaukee-Eight 121 High Output (HO) |
| Oil Type | Screamin’ Eagle SYN3 Full Synthetic 20W50 |
| Oil Capacity | 4.5 Liters (4.75 US qt) |
| Front Tire | 130/60B19 61H |
| Rear Tire | 180/55B18 80H |
| Spark Plug | H-D 31600012 |
| Battery | 66000643 |
The 2024 Harley-Davidson CVO Road Glide ST represents a pivotal moment in American bagger engineering. It marks the first time a production ‘Grand American Touring’ model has featured a 5,900 RPM redline, achieved through the implementation of a high-performance camshaft and a unique oval intake system designed specifically for the 121 High Output (HO) V-Twin. This isn’t just a larger engine; it is a high-revving performance unit that shifts the paradigm of the CVO line from pure luxury to track-inspired capability.
Engineering Highlight: The 121 High Output Powertrain
Unlike the standard 121 VVT engine, the ST variant utilizes the 121 HO configuration. By removing Variable Valve Timing in favor of a dedicated high-lift cam and optimized induction, H-D engineers increased peak horsepower to 127 hp and torque to 145 lb-ft. This power is managed via a final drive ratio optimized for acceleration, making the FLTRXSTSE the fastest-accelerating bagger in the current H-D catalog.
Chassis and Weight Reduction
To support the increased power, the FLTRXSTSE features significant unsprung weight reduction. The use of carbon fiber components—including the front fender, seat cowl, and tank console—along with lightweight forged wheels, reduces the curb weight by approximately 25 lbs compared to the standard CVO Road Glide. The suspension is handled by fully adjustable Showa components, featuring a remote-adjust rear monoshock and 47mm inverted forks.
Maintenance Guide & Technical Specifications
Maintaining the 121 HO engine requires strict adherence to high-performance fluid standards. At MotoSpecsLab, we recommend the following service parameters:
- Lubrication: Use 4.5 liters of Screamin’ Eagle SYN3 Full Synthetic 20W50. This is critical for managing the higher thermal loads produced by the HO engine’s increased RPM ceiling.
- Ignition: The 121 HO utilizes high-performance spark plugs (Part No. 31600012). Check gaps every 5,000 miles to ensure optimal combustion efficiency.
- Tire Maintenance: The Dunlop Harley-Davidson Series tires require precise pressure management for handling stability. Front: 2.5 bar (36 psi). Rear: 2.9 bar (42 psi).
- Electrical: The model uses the high-output 66000643 battery to support the advanced Infotainment system and the high-compression starter motor.
MotoSpecsLab Editorial Verdict
The CVO Road Glide ST is a masterclass in performance-oriented luxury. While the price point is premium, the mechanical upgrades—specifically the 121 HO engine and the Showa suspension—provide a tangible performance delta over any other production H-D bagger. It is a technical achievement that successfully bridges the gap between the King of the Baggers racing series and the showroom floor.