BMW R 18 Roctane (K35) — OEM Fluid, Tire Pressure & Maintenance Specs
1,802cc Air/Oil-Cooled Big Boxer Twin OHV Pushrod · Source: BMW R 18 Roctane (K35) (2023–Present) Official Owner’s Manual Maintenance Specifications
According to the BMW R 18 Roctane (K35) (2023–Present) Official Owner’s Manual Maintenance Specifications, the 2023–Present BMW R 18 Roctane (K35) (chassis K35/0L33) requires 3.6 L (3.80 US qt) of SAE 15W-50 (JASO MA2, API SJ / BMW Advantec Pro 15W-50) engine oil for a drain-only change and 4 L (4.23 US qt) with filter service (11427673541 / HF164). Standard solo cold tire pressure is 290 kPa / 2.90 bar / 42 PSI front (120/70 B21) and 320 kPa / 3.20 bar / 46 PSI rear (180/55 B18), paired with 2× NGK MAR8AI-10DS spark plug(s) and a BMW 26Ah AGM battery.
Drain only: 3.6 L (3.80 US qt)
R 320 kPa (3.20 bar)
Est. Range: ~280 km (174 mi)
1. Engine Lubrication, Filter & Clutch Specifications
| Clutch Architecture | Dry Single-Plate Manual Clutch (Separate Gearbox Oil) |
|---|---|
| Recommended Viscosity & Grade | SAE 15W-50 (Alt: SAE 20W-50) · JASO MA2 · API SJ / BMW Advantec Pro 15W-50 |
| Oil Volume (Drain / With Filter / Overhaul) |
• Drain only: 3.6 L (3.80 US qt) • With filter/strainer: 4 L (4.23 US qt) • Complete dry overhaul: 4.5 L (4.76 US qt) |
| OEM Oil Filter Code & Type | 11427673541 / HF164 |
| Correct Oil Level Check Method | Hold bike upright on level ground 3–5 min after warm shutdown; read crankcase sight glass |
| Oil Drain Bolt Torque | 32 N·m (23.6 lb-ft / 3.26 kgf·m) — Use fresh crush washer |
| Separate Transmission / Gearbox Oil | 1100 ml (1.10 L) — SAE 75W-90 GL-5 (800 ml separate manual gearbox) |
| Final Drive / Bevel Gear Oil | 200 ml (0.20 L) — SAE 75W-90 Hypoid Axle Oil (180 ml Paralever bevel drive) |
2. Cold Tire Pressures, Wheels, Ignition & Drivetrain
| Front / Rear OEM Tire Sizes | Front: 120/70 B21 · Rear: 180/55 B18 (Tubeless) |
|---|---|
| Cold Tire Pressure — Solo Riding |
Front: 290 kPa / 2.90 bar / 42 PSI Rear: 320 kPa / 3.20 bar / 46 PSI |
| Cold Tire Pressure — 2-Up / Loaded Touring |
Front: 290 kPa / 2.90 bar / 42 PSI Rear: 320 kPa / 3.20 bar / 46 PSI |
| OEM Spark Plug & Quantity | NGK MAR8AI-10DS × 2 (Gap: 0.8 mm) |
| OEM Battery Code & Rating | BMW 26Ah AGM (12V 14.0Ah MF AGM) |
| Final Drive Maintenance | Cardan Shaft Final Drive — Replace rear bevel-gear hypoid oil at exact measured volume |
| Brake Fluid & Coolant | DOT 4 · Air/Oil-Cooled Engine (No liquid coolant) |
3. Ergonomics, Range & Scheduled Service Intervals
| Displacement · Max Power · Peak Torque | 1802 cc · 91 hp @ 4,750 rpm · 158 N·m (116.5 lb-ft) @ 3,000 rpm |
|---|---|
| Seat Height & Wet Curb Weight | 720 mm (28.3 in) · 374 kg (825 lbs) |
| Fuel Tank & Est. Real-World Range | 16 L (4.2 US gal) · ~17.5 km/L → ~280 km (174 mi) |
| OEM Scheduled Maintenance Intervals |
• First Break-In: 1,000 km • Engine Oil / Filter: 10,000 km / 10,000 km • Air Filter / Spark Plug: 20,000 km / 20,000 km • Valve Clearance Check: 10,000 km |
4. Generation Cutoffs & Real-World Wrenching Gotchas
Model-Year & Chassis Generation Notes
Blacked-out hot-rod K35 custom bagger rolling on a tall 21-inch front wheel, mid-ape handlebars, vintage round instrument pod, and color-matched 27 L hard cases.
Oil & Clutch Mechanical Engineering Note
BMW air/oil-cooled Boxer platform (R 1150, K25 R 1200, R nineT family, R 12, R 18) featuring an automotive dry single-plate clutch with separate engine, gearbox, and shaft bevel oils.