This also applies to the total weight of the vehicle

This also applies to the total weight of the vehicle

The racing motorcycle is built according to these ideas. The frame is a triangular composite made of thin-walled precision stainless steel tubing, which has rarely been used in motorcycle construction so far. Two pipe bends lead from the control head over the engine to the swing arm bearing. Towards the front, the swing arm bearing is supported against the control head by two straight tubes over the shortest possible distance. This design requires minimal use of materials. This results in an unprecedentedly favorable stiffness-to-weight ratio. This frame layout was made possible not only by the aforementioned clutch positioning on the crankshaft, but also by the cylinder being tilted far forward.

The rear frame is formed by light square tubes made of light alloy, which are bolted to the main frame. Practical to solve was the coaxial bearing of the swing arm and the chain pinion. In the present design, the swingarm axle mounted in the frame passes through the hollow-bored transmission output shaft, which carries the drive pinion. To change the sprocket, the motorcycle is jacked up, the swingarm axle is pulled out and the swingarm with the installed wheel is folded backwards. A skilled mechanic needs approx. 15 minutes. The other chassis elements are conventional. Corresponding to the high class standard. A fully adjustable upside-down fork from Marzocchi with a travel of 300 mm is used as front wheel guide. Suspension and damping of the rear wheel is handled by a direct-acting, progressive Öhlins strut with 320 mm travel. When set at an angle, it is supported directly on the stiff main frame, so the rear frame only has to take the load of the rider.

The competition prototype is powered by a BMW-designed 450 cubic centimeter high-performance single-cylinder four-stroke engine with two overhead camshafts and dry-sump lubrication. A special feature and so far unique in this class is the fuel injection and lambda control system. As already mentioned, the cylinder position, which is tilted far forward, allows almost straight intake air ducting into the large-volume airbox located above the engine. This offers the best conditions for optimum engine performance tuning.

The tank position under the rider's seat, with all its advantages in terms of center of gravity, is well known from other BMW single-cylinder motorcycles. The position of the clutch on the right-hand crankshaft stub is also unique. It could be very compactly dimensioned because it runs at engine speed due to the lack of reduction of the primary drive and consequently has to transmit a lower torque. Power is transmitted from the crankshaft to the transmission via an intermediate shaft with integrated breather function. An electric starter is mandatory.

The chain drive to the rear wheel does not require additional tensioning devices and guides due to the hardly necessary sag and the constant length of the chain – this also saves weight. The load change influence on the drive is reduced, the chain load is lowered and even generous chain encapsulations would be conceivable. The performance data of the engine are on competition level, detailed data remain reserved for a later time. This also applies to the total vehicle weight, already the first concept vehicle reaches values in the order of magnitude of the established representatives of this vehicle class.

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