BMW R 25 (1950–1951) — Specs
Identity
Manufacturer: BMW
Model: R 25
Category: Motorcycle
Type: Motorcycle
Years: 1950 → 1951
Engine
Displacement (cc): 247
Cylinders: 1
Power (hp): 12
Power (kW): 9
Torque (Nm): 12
Dimensions
Overall length: 2070 mm
Overall width: 770 mm
Overall height: 1130 mm
Wheelbase: 1395 mm
Ground clearance: 155 mm
Weight (kg): 140
Seat height (mm): 710
Tank (L): 12
Tires
Front pressure (bar): 1.5
Rear pressure (bar): 1.6
Drivetrain
Drive chain: shaft drive
Ignition
Spark plug: NGK B8HS
Plug gap: 0.6 mm
Fluids & Filters
Engine oil (with filter, L): 1.25
Oil filter: OEM oil filter
Air filter: OEM air filter
Brake fluid: DOT 4
Fuel consumption
Estimated range: ~400 km on a full tank (12.0 L)
Service
Battery: OEM battery specification
Service interval (km): 6000
Service interval (months): 12
Valve check (km): 12000
Parts and consumables for this motorcycle
Data is gathered with care, but without guarantee. Always confirm critical information with your dealer or workshop.
Service notes
Service interval: every 6,000 km or 12 months, whichever comes first. Valve clearance check every 12,000 km. Valve clearance — intake cold 0.10-0.15 mm, exhaust cold 0.15-0.20 mm. Engine oil: 1.25 L with filter change. Spark plug: NGK B8HS (gap 0.6 mm). Drive: shaft drive. Tire pressure: front 1.5 bar, rear 1.6 bar (cold). Always confirm critical values with the workshop manual or an authorised dealer.
OEM and quality aftermarket parts that fit this bike. Always confirm with your dealer before ordering.
Engine oil
Spec: nan, 1.25 L (with filter)
- OEM OEM recommended engine oil
- Premium Motul 7100 4T (100% Synthetic, Ester)
- Premium Motul 5100 4T Technosynthese (Semi-Synthetic)
Which Motul for this bike?
| Motul 7100 4T ✓ | Motul 5100 4T | |
|---|---|---|
| Product | Motul 7100 4T — 100% fully synthetic | Motul 5100 4T — semi-synthetic |
| Best for | Sport, Naked, Adventure (600cc+), track | Standard, Cruiser, Scooter, daily use |
| RPM protection | Excellent — ester base, stable under load | Good — for normal riding conditions |
- Standard Repsol Moto Racing 4T (Synthetic)
- Standard Elf Moto 4 Tech (Semi-Synthetic)
Fully Synthetic vs Semi-Synthetic
| Fully Synthetic | Semi-Synthetic | |
|---|---|---|
| Base oil | 100% chemical synthesis (ester or PAO) | Mineral oil + synthetic additives |
| Heat resistance | Excellent — stable at extreme heat & RPM | Good — suitable for normal temperatures |
| Cold start | Better — reaches engine faster when cold | Good — adequate for normal climates |
| Change interval | Longer (up to 10,000 km) | Shorter (5,000–7,000 km typical) |
| Price | Higher | Lower |
Oil filter
- OEM OEM oil filter
- Premium Hiflofiltro – check by VIN at hiflofiltro.com
- Premium K&N – check fitment by VIN at knfilters.com
- Standard Champion COF
- Standard Vesrah SF
Air filter
- OEM OEM air filter
- Premium K&N Replacement Air Filter
- Premium DNA High Performance
- Standard Hiflofiltro air filter – check by VIN
- Standard Champion CAF
Spark plug
Spec: NGK B8HS, gap 0.6 mm
- OEM NGK B8HS
- Premium NGK B8HSIX
- Premium Denso Iridium Power
- Standard NGK B8HS
- Standard Denso Standard
Front brake pads
Spec: EBC FA121HH
- OEM OEM front brake pads
- Premium Brembo Z04 / SC
- Premium EBC FA121HH
- Standard Ferodo Platinum
- Standard TRW Lucas Sintered
Rear brake pads
Spec: EBC FA121HH
- OEM OEM rear brake pads
- Premium Brembo SP
- Premium EBC FA121HH
- Standard Ferodo Platinum
- Standard TRW Lucas
Front tire
Spec: 1.5 bar
- OEM OEM front tire size as specified by manufacturer
- Premium Michelin Road / Power
- Premium Pirelli Diablo / Angel
- Standard Metzeler Roadtec / Tourance
- Standard Dunlop Sportmax / Trailmax
Rear tire
Spec: 1.6 bar
- OEM OEM rear tire size as specified by manufacturer
- Premium Michelin Road / Power
- Premium Pirelli Diablo / Angel
- Standard Metzeler Roadtec / Tourance
- Standard Dunlop Sportmax / Trailmax
Battery
- OEM OEM battery specification
- Premium Yuasa YTX7L-BS or YTX7A-BS (typical 125-250cc)
- Premium Motobatt Quadflex
- Standard Exide AGM
- Standard Varta Powersports
Brake fluid
- OEM OEM recommended brake fluid
- Premium Motul RBF 600 / 660
- Premium Castrol React SRF
- Standard TotalEnergies HBF4
- Standard Elf BRAKE FLUID DOT 4
Coolant
- OEM OEM recommended coolant
- Premium Motul Motocool Factory Line
- Premium Engine Ice
- Standard TotalEnergies Coolelf
- Standard Elf Coolelf Auto Supra
Service interval
Spec: 6 000 km / 12 months
- OEM Engine oil + oil filter change
- OEM Air filter inspection
- OEM Spark plug check
- OEM Brake fluid replacement: every 2 years
Valve check
Spec: 12 000 km
- OEM Intake clearance: cold 0.10-0.15 mm
- OEM Exhaust clearance: cold 0.15-0.20 mm
Suspension
Spec: telescopic fork / 130 ml SAE 30
- OEM Fork: telescopic fork
- OEM Fork oil grade: 130 ml SAE 30
Drive chain
- OEM OEM chain (matches OEM pitch and length)
- Premium DID VX3 X-Ring
- Premium DID ZVM-X Pro
- Standard JT Sprockets HDR
- Standard AFAM A5
