| Specification | Data |
|---|---|
| Production Years | 1988 – 1993 |
| Engine Oil | SAE 20W-50 (API SF/SG/SH) – 3.75 L |
| Tire Dimensions | F: 120/70 ZR 17 / R: 160/60 ZR 18 |
| Spark Plugs | Bosch XR 5 DC (Gap: 0.60 – 0.70 mm) |
| Battery | DIN 519 13 (12V 19Ah) |
Did you know? The BMW K 1 was the first production motorcycle to achieve a drag coefficient (Cd) of just 0.34 with the rider tucked, thanks to its seven-piece glass-fiber reinforced plastic fairing. This was not merely a design choice; it was a technical necessity to bypass the 100-horsepower limit imposed by German manufacturers at the time, allowing the bike to reach top speeds exceeding 240 km/h (150 mph) through aerodynamic efficiency rather than raw power.
Technical Overview: The Evolution of the ‘Flying Brick’
The BMW K 1 represented a radical departure from the traditional touring image of the K series. While it utilized the legendary longitudinal four-cylinder engine layout, it was the first BMW to feature a 16-valve cylinder head and the advanced Motronic engine management system. This technical leap provided the K 1 with a smoother power delivery and improved thermal efficiency compared to its 8-valve predecessors.
The chassis featured the Paralever rear suspension, which significantly reduced the shaft-drive ‘jacking’ effect, providing a more stable platform during aggressive cornering. Despite its long wheelbase and heavy weight, the K 1 remains a marvel of high-speed stability and engineering ambition.
Maintenance Guide & Service Requirements
Lubrication System
To maintain the longevity of the 16-valve head, MotoSpecsLab recommends high-quality SAE 20W-50 oil. The engine requires 3.75 liters during a full oil and filter change. Given the tight tolerances of the Motronic system, stick strictly to API SF, SG, or SH classifications to avoid clutch contamination in the separate gearbox housing.
Ignition & Electrical
The K 1 relies on Bosch XR 5 DC spark plugs. For optimal combustion, the gap must be precisely set between 0.60 mm and 0.70 mm. Given the aerodynamic bodywork, heat dissipation is a factor; ensure the cooling system is flushed regularly to prevent the ‘hot foot’ syndrome common to early K models. The electrical system is powered by a robust 12V 19Ah battery (DIN 519 13).
Tires and Handling
The K 1 uses a unique staggered rim setup. Correct tire pressure is critical for managing the bike’s 258kg wet weight:
- Front (120/70 ZR 17): 2.2 bar (31.9 psi) for solo riding; 2.5 bar (36.3 psi) when loaded.
- Rear (160/60 ZR 18): 2.5 bar (36.3 psi) for solo riding; 2.9 bar (42.1 psi) when carrying a passenger or luggage.
MotoSpecsLab Verdict
The BMW K 1 is more than a motorcycle; it is a rolling laboratory of late-80s German engineering. While its turning circle is notoriously wide, its high-speed composure is legendary. For the modern collector, maintaining the integrity of the ABS system and the integrity of the fairing mounts is paramount to preserving this aerodynamic pioneer.