| Attribute | Specification |
|---|---|
| Production Years | 1998-2005 |
| Engine Type | Air/Oil-cooled Boxer Twin (8-valve) |
| Oil Requirement | SAE 20W-50 (API SE, SF, SG) / 3.75 Liters |
| Battery | 51913 (12V 19Ah AGM) |
| Tire Pressure (Solo) | F: 2.2 bar / R: 2.5 bar |
Representing a radical departure from the conservative styling of the late 90s, the BMW R 1100 S (0422/259) holds the distinction of being BMW’s first true entry into the modern sport-touring segment. It was the first Boxer-powered motorcycle to feature an under-seat exhaust system—a design choice that emphasized its performance intentions—and was the most powerful Boxer engine of its time, finally breaking the 100-horsepower barrier for the brand’s production twins.
Engineering Overview
The R 1100 S is built around the ‘259’ engine architecture, utilizing the engine as a stressed member of the chassis. This ‘frameless’ design, coupled with the Telelever front suspension and Paralever rear swingarm, provides a unique anti-dive geometry that remains a hallmark of BMW engineering. The 0422 internal designation refers specifically to the refinement of this platform, which balances high-speed stability with the mechanical character of the 1085cc flat-twin.
Maintenance Essentials
Lubrication System
The air/oil-cooled engine is highly dependent on oil viscosity for thermal management. MotoSpecsLab recommends SAE 20W-50 with high ZDDP content (API SE, SF, or SG) to protect the flat-tappet cam followers. Total capacity with filter change is 3.75 Liters.
Ignition System Evolution
Technicians must distinguish between the two ignition phases of this model:
- Single Spark (1998–2002): Uses two NGK BKR7EKC plugs.
- Twin Spark (2003–2005): Introduced to solve surging issues at low RPM. It utilizes an NGK BKR7EKC as the primary plug and a smaller NGK DCPR8EKC as the secondary (bottom) plug.
Wheel and Tire Configuration
The R 1100 S came with two rear wheel options. The standard 5.0-inch rim takes a 170/60 ZR 17, while the optional 5.5-inch ‘Sport’ rim requires a 180/55 ZR 17. For optimal handling, maintain pressure at 2.2 bar (Front) and 2.5 bar (Rear) when riding solo.
Critical Inspection Points
As these machines age, MotoSpecsLab advises owners to pay close attention to the input shaft splines. Unlike chain-driven bikes, the dry clutch configuration requires periodic lubrication of the transmission splines to prevent premature wear. Additionally, the early ABS II and later iABS (Servo) systems require bi-annual fluid flushes to ensure the longevity of the control modules.
Summary
The BMW R 1100 S remains a pinnacle of German engineering for enthusiasts who value mechanical feedback over electronic intervention. By adhering to the precise fluid and ignition specifications outlined above, owners can ensure this modern classic continues to perform at its 1998-era peak.