| Component | Specification |
|---|---|
| Engine | Milwaukee-Eight 114 V-Twin |
| Oil Type | SAE 20W-50 |
| Oil Capacity | 4.3 Liters (4.5 US qt) |
| Front Tire | 130/90B16 67H |
| Rear Tire | 150/80B16 77H |
| Tire Pressure (F/R) | 36 psi / 40 psi |
| Battery | OEM Part 66000207 |
| Spark Plug | H-D 6R10 |
While the Heritage Softail nameplate dates back to 1986, the 2018-Present FLHCS represents a radical engineering departure: the introduction of the Milwaukee-Eight 114 engine into a completely redesigned Softail chassis that is 34% stiffer and significantly lighter than its predecessor. This iteration successfully merged the classic ‘Hardtail’ aesthetic with modern mono-shock suspension hidden beneath the seat, effectively ending the era of the counter-balanced Twin Cam B engines in favor of the more refined dual-counterbalanced M8 platform.
Engineering Overview: The Milwaukee-Eight 114
The heart of the FLHCS is the 1,868cc Milwaukee-Eight 114 engine. Unlike traditional air-cooled V-twins, this unit features precision oil-cooled cylinder heads and a four-valve per cylinder design. This configuration allows for a higher compression ratio (10.5:1) and significantly better thermal management, which is critical for maintaining performance during long-distance touring. The dual spark plugs per cylinder ensure efficient combustion and reduced emissions without sacrificing the signature Harley-Davidson torque curve.
Maintenance Guide & Fluid Specifications
For the professional technician or the dedicated owner, adhering to the following specifications is paramount for the longevity of the M8 powertrain:
- Engine Lubrication: The system requires 4.3 Liters of SAE 20W-50. For optimal performance in varying temperatures, MotoSpecsLab recommends full synthetic lubricants meeting the JASO MA2 standard to protect the integrated primary and transmission systems.
- Ignition System: The FLHCS utilizes H-D 6R10 spark plugs. Proper gapping is essential to prevent misfires in the high-torque 114 CUI environment.
- Electrical: The 66000207 battery provides the high cold-cranking amps (CCA) required to turn over the massive 114 cubic inch pistons.
Chassis and Handling
The FLHCS is equipped with high-performance front suspension featuring ‘Show Dual Bending Valve’ (SDBV) technology, which provides the damping performance of a racing-style cartridge fork but with lighter weight. The rear features a high-performance mono-shock with easy-to-reach under-seat hydraulic preload adjustment, allowing riders to tune the suspension for passenger and luggage weight instantly.
Tire & Safety Specifications
Proper tire maintenance is the most critical safety factor for a 728 lb (wet weight) cruiser. The Heritage 114 runs on a 130/90B16 front and a 150/80B16 rear. Pressure must be maintained at 2.5 bar (36 psi) for the front and 2.8 bar (40 psi) for the rear to ensure predictable cornering and to prevent premature cupping of the tread.
Frequently Asked Questions
How often should the oil be changed?
Harley-Davidson recommends a service interval of 5,000 miles (8,000 km), though many enthusiasts opt for 3,000-mile intervals if riding in extreme heat or stop-and-go traffic.
What is the benefit of the 114 over the 107 engine?
The 114 CUI engine offers approximately 9% more torque (119 ft-lb vs 109 ft-lb), providing better roll-on acceleration, especially when the bike is fully loaded with gear and a passenger.