| Specification | Data |
|---|---|
| Model Variant | F 650 GS Dakar – F650DAK/04 |
| Production Years | 2004–2007 |
| Engine Oil | SAE 15W-50 API SJ/JASO MA2 (2.3 L) |
| Tires (F/R) | 90/90 – 21 / 130/80 – 17 |
| Spark Plugs | 2 x NGK DR8EB |
| Battery | YB12AL-A2 |
The BMW F 650 GS Dakar represents a pivotal moment in adventure motorcycling history. While many believe the ‘Dakar’ moniker was purely aesthetic, the F650DAK/04 (the 2004-2007 “Dual Spark” R13 evolution) featured a unique 21-inch front wheel and significantly longer suspension travel compared to the standard GS, directly inspired by Richard Sainct’s back-to-back victories in the Paris-Dakar Rally. This specific iteration introduced the BMS-C II fuel injection system and dual-spark ignition, which rectified the surging issues found in earlier single-spark models.
Engineering Overview: The Rotax Heart
At the core of the F650DAK/04 is the liquid-cooled, single-cylinder Rotax engine. The 2004 update was not merely a cosmetic facelift. By utilizing two spark plugs (NGK DR8EB), BMW achieved more complete combustion, reducing emissions to meet Euro 2 standards while flattening the torque curve. This makes the Dakar variant exceptionally tractable in low-speed technical off-road sections.
Maintenance & Technical Specifications
Proper maintenance is critical for the longevity of this dry-sump engine. Note that the oil level must be checked when the engine is at full operating temperature, as the oil resides in a frame-mounted tank.
Lubrication and Fluids
- Viscosity: SAE 15W-50 is the gold standard for this engine, ensuring stable film strength in high-heat environments.
- Capacity: 2.3 Liters (including filter change).
- Coolant: Ethylene glycol-based, silicate-free (approx. 1.2 L).
Chassis and Contact Patch
The Dakar’s off-road prowess relies on its 21-inch front rim. Maintaining precise tire pressures is essential for both rim protection and pavement stability:
- Solo: Front 1.9 bar (27.5 psi) | Rear 2.1 bar (30.5 psi)
- With Passenger: Front 2.1 bar (30.5 psi) | Rear 2.3 bar (33.4 psi)
Editor’s Verdict
The F650DAK/04 remains one of the most fuel-efficient adventure bikes ever produced, often exceeding 65 mpg. Its combination of a low center of gravity (due to the under-seat fuel tank) and the 21-inch front wheel makes it a superior choice for transcontinental travel where reliability is paramount. It is a masterclass in functional engineering from the pre-electronic-aid era.
Frequently Asked Questions (FAQ)
Q: Why does my Dakar require two spark plugs?
A: The dual-spark system (introduced in 2004) improves combustion efficiency, provides smoother throttle response, and helps the bike meet stricter emission regulations without sacrificing power.
Q: Can I use 10W-40 oil?
A: While 10W-40 is acceptable in very cold climates, the manufacturer specifically recommends 15W-50 for the F650DAK/04 to ensure adequate protection for the integrated gearbox and wet clutch.