Harley-Davidson Nightster / Nightster Special (RH975) — OEM Fluid, Tire Pressure & Maintenance Specs
975cc Liquid-Cooled 60° V-Twin DOHC Intake-VVT Revolution Max 975T (Unit Wet Clutch) · Source: Harley-Davidson Nightster (RH975 / RH975S) Official Owner’s Manual
According to the Harley-Davidson Nightster (RH975 / RH975S) Official Owner’s Manual, the 2022–Present Harley-Davidson Nightster / Nightster Special (RH975) (chassis RH975/RH975S (Special)) requires 4 L (4.23 US qt) of SAE 15W-50 (JASO MA2, API SN+ / JASO MA2 Full Synthetic (H-D SYN Blend 15W-50)) engine oil for a drain-only change and 4.5 L (4.76 US qt) with filter service (HD 62700280 (Revolution Max Specific)). Standard solo cold tire pressure is 214 kPa / 2.14 bar / 31 PSI front (100/90B19 57H) and 276 kPa / 2.76 bar / 40 PSI rear (150/80B16 77H), paired with 2× HD 31600190 (Single-Plug per Cylinder on 975T) spark plug(s) and a HD 66000340 AGM battery.
Drain only: 4 L (4.23 US qt)
R 276 kPa (2.76 bar)
Est. Range: ~234 km (145 mi)
1. Engine Lubrication, Filter & Clutch Specifications
| Clutch Architecture | Wet Multi-Plate Manual Clutch NEVER use JASO MB |
|---|---|
| Recommended Viscosity & Grade | SAE 15W-50 (Alt: SAE 20W-50 (Screamin’ Eagle SYN3)) · JASO MA2 · API SN+ / JASO MA2 Full Synthetic (H-D SYN Blend 15W-50) |
| Oil Volume (Drain / With Filter / Overhaul) |
• Drain only: 4 L (4.23 US qt) • With filter/strainer: 4.5 L (4.76 US qt) • Complete dry overhaul: 5 L (5.28 US qt) |
| OEM Oil Filter Code & Type | HD 62700280 (Revolution Max Specific) |
| Correct Oil Level Check Method | At full operating temperature resting ON THE SIDESTAND (Jiffy Stand); thread dipstick in to read |
| Oil Drain Bolt Torque | 22 N·m (16.2 lb-ft / 2.24 kgf·m) — Use fresh crush washer |
2. Cold Tire Pressures, Wheels, Ignition & Drivetrain
| Front / Rear OEM Tire Sizes | Front: 100/90B19 57H · Rear: 150/80B16 77H (Tubeless) |
|---|---|
| Cold Tire Pressure — Solo Riding |
Front: 214 kPa / 2.14 bar / 31 PSI Rear: 276 kPa / 2.76 bar / 40 PSI |
| Cold Tire Pressure — 2-Up / Loaded Touring |
Front: 214 kPa / 2.14 bar / 31 PSI Rear: 290 kPa / 2.90 bar / 42 PSI |
| OEM Spark Plug & Quantity | HD 31600190 (Single-Plug per Cylinder on 975T) × 2 (Gap: 0.8–0.9 mm) |
| OEM Battery Code & Rating | HD 66000340 AGM (12V 12.0Ah Sealed AGM) |
| Final Drive Maintenance | Harley-Davidson Carbon-Reinforced Belt — Zero lube required, periodic tension check |
| Brake Fluid & Coolant | DOT 4 · Harley-Davidson Genuine Extended Life Antifreeze & Coolant |
3. Ergonomics, Range & Scheduled Service Intervals
| Displacement · Max Power · Peak Torque | 975 cc · 89 hp @ 7,500 rpm · 95 N·m (70.1 lb-ft) @ 5,750 rpm |
|---|---|
| Seat Height & Wet Curb Weight | 705 mm (27.8 in) · 221 kg (487 lbs) |
| Fuel Tank & Est. Real-World Range | 11.7 L (3.1 US gal) · ~20 km/L → ~234 km (145 mi) |
| OEM Scheduled Maintenance Intervals |
• First Break-In: 1,600 km • Engine Oil / Filter: 8,000 km / 8,000 km • Air Filter / Spark Plug: 24,000 km / 48,000 km • Valve Clearance Check: 48,000 km |
4. Generation Cutoffs & Real-World Wrenching Gotchas
Model-Year & Chassis Generation Notes
Succeeding the air-cooled Iron 883, the liquid-cooled Nightster (RH975) shares its unit crankcase architecture with the Sportster S (RH1250S), but its 975T engine runs intake-only VVT and 2 spark plugs total (1 per cylinder) instead of 4. The 2023+ Nightster Special (RH975S) adds 4-inch TFT, pillion seat, TPMS, and cruise control.
Oil & Clutch Mechanical Engineering Note
Unlike 2-hole Evolution Sportsters, the Revolution Max 975T uses unit construction—one 4.5 L service fill of SAE 15W-50 JASO MA2 with filter HD 62700280 lubricates engine, gearbox, and wet slipper clutch, while hydraulic lash adjusters eliminate routine valve adjustments.
Garage Wrenching Gotchas
- The traditional steel peanut silhouette up top is actually the airbox cover—the real 11.7 L fuel cell sits under the hinged rider seat, dramatically lowering center of gravity.
- Always check Revolution Max 975T oil HOT while resting on the sidestand (Jiffy Stand), screwing the dipstick fully in to read—never check upright.
5. Frequently Asked Questions (FAQ)
Does the Harley-Davidson Nightster 975 require separate primary fluid like an Iron 883?
No—the Nightster’s liquid-cooled 975T is a shared-sump unit engine. A single drain-and-fill of 4.5 L (4.75 US qt) of SAE 15W-50 JASO MA2 with filter 62700280 covers engine, clutch, and transmission.
How many spark plugs does the Nightster 975 use compared to the Sportster S?
Unlike the dual-plug 1250 models (4 plugs), the 975T cylinder heads use a single central plug per cylinder—2 spark plugs total (HD 31600190).
What is the factory cold tire pressure for the Harley Nightster 975?
Cold inflation is 31 PSI (214 kPa) front (100/90B19) and 40 PSI (276 kPa) rear (150/80B16), or up to 42 PSI (290 kPa) rear two-up.