| Specification | Value |
|---|---|
| Model Year | 2017 |
| Engine Oil | SAE 20W50 Harley-Davidson 360 (2.8 L) |
| Tires (Front/Rear) | F: MT90B16 72H / R: MU85B16 77H |
| Tire Pressure | F: 36 psi / R: 40 psi |
| Battery Code | 65989-97E |
| Spark Plug | 6R12 |
Engineering Highlight: The Final Twin Cam Legacy
The 2017 Harley-Davidson Softail Slim (FLS/17) holds a significant place in motorcycling history as the final iteration of the High Output Twin Cam 103B engine within the Softail chassis. Unlike the Dyna models of the same era, the ‘B’ variant utilized twin counter-balancers to manage primary vibrations, allowing the engine to be rigid-mounted to the frame. This engineering choice provided the iconic ‘hardtail’ look while maintaining the Euro 4 compliance necessary for global distribution.
Performance & Powertrain
The FLS/17 is powered by the 1,690cc (103 cubic inch) V-Twin. With the Euro 4 refinement, the fueling map was optimized for leaner emissions without sacrificing the low-end torque characteristic of the platform. Peak torque is reached early in the rev range, making it an exceptional cruiser for urban environments and scenic highways alike. The 6-Speed Cruise Drive transmission provides smooth shifting, though the hydraulic clutch system requires periodic inspection to ensure consistent engagement.
Maintenance Essentials
For the professional technician or the dedicated owner, adhering to the following specifications is critical for longevity:
- Lubrication: Use 2.8 Liters of SAE 20W50 HD 360. In extreme temperature conditions, synthetic alternatives may be used, but the viscosity grade must remain consistent to protect the internal balancers.
- Electrical: The 65989-97E battery is a high-CCA (Cold Cranking Amps) unit. Given the compression of the 103 engine, ensuring clean terminal connections is vital to prevent starter clutch wear.
- Ignition: The 6R12 spark plugs should be gapped according to factory service manuals to ensure complete combustion and prevent Euro 4 sensor fouling.
Chassis & Handling
The Softail Slim is defined by its ‘Hollywood’ handlebars and narrow rear profile. To maintain the intended handling geometry, tire pressures must be strictly monitored. The MT90B16 front and MU85B16 rear combination provides a stable contact patch, but the heavy weight of the chassis means that running even 5 psi low can significantly increase steering effort and promote uneven tread wear.
Expert Verdict
The 2017 FLS/17 represents the pinnacle of ‘Analog’ Harley-Davidson engineering before the digital integration of the Milwaukee-Eight era. It is a robust, mechanically transparent motorcycle that rewards regular maintenance with incredible reliability and a timeless riding experience.
Frequently Asked Questions
What is the oil capacity for the FLS/17?
The Softail Slim (2017) requires 2.8 Liters of SAE 20W50 Harley-Davidson 360 oil.
What are the correct tire pressures?
The front tire should be set to 36 psi (2.48 bar) and the rear tire to 40 psi (2.76 bar).
Which spark plugs should I use?
The factory-recommended spark plugs are the Harley-Davidson 6R12.