Herewith brief translation summary of the recent issue of Das Motorrad, with the newest photos and Motorrad's conceptual sketches of the new machine. offered by Kari Prager. This is speculation and is not an official press release from BMW Motorrad.
MOTORRAD, Volume 22, October 10th 2003
BMW is building a completely new four-cylinder machine, new not only for BMW but for the entire motorcycle industry. Motorrad has the world's exclusive unveiling of the new technology in the BMW of the future.
BMW always can be counted on for surprises! While the motorcycle industry let their single cylinder models languish, BMW launched the F 650 series with great success. And while all the other manufacturers struggled with the shortcomings of the telescopic fork, BMW led the way with an entirely new approach to front suspension, the Telelever, whose compelling advantages forced the other chassis engineers to sit up and take notice. BMW convinced its customers of the value of ABS, three-way catalytic converters, and shaft drive with the shaft reaction eliminated, while the ompetition offered "Faster, Stronger, Lighter", over and over again. Thus it has been until today, and after today all will be different! The new K BMW displays not only sensational technology, it will also be "Faster, Stronger, Lighter". Much, much stronger and faster than its BMW predecessors.
The new K advances to the rank of powerful sport tourers in the class of a HondaCBR 1100 XX or even a Suzuki GSX 1300 R Hayabusa. The motor, mounted perpendicular to the direction of travel, like most Japanese bikes, is conceived to have a displacement range of 1000 to 1300 cc., and the Bavarian sport tourer will probably launch with 1200 or 1300. A solid 160 to 170 horsepower output should satisfy the most power-mad enthusiast. Blessed with a 285 km/h top speedand explosive torque, the new BMW needs to bow its head to noone. Very important: The bike is shaft-driven. In spite of this, the weight, tanked up and ready to go, will be under 250 Kg, and this is with the centerstand. Typical BMW: The fairing, developed in the wind tunnel, will offer optimal wind protection. Rider and passenger will be competely comfortable. A four-into-one exhaust system on the right side sounds a sporty note. In regards to safety and environment, a new ABS system and the most modern catalytic technology roundout the BMW program. Naturally this sport tourer is only the beginning of a new model series. Anything is possible, all the way to a spectacular naked-bike!
The world has never seen anything like this in the world of mass production! BMW has demonstrated that the Telelever was just the first step in a new technology. Now the engineers are taking the next step with an integrated package of double A-Arm front suspension, single-sided swingarm rear suspension, and a flat-sided, practically horizontal frame (literally Bridge-frame). This allows for a low overall height and low center of mass, a much shorter wheelbase in comparison to the current K, and a stiffer suspension for the front wheel. The rear wheel suspension is finally equipped with a rising-rate linkage. The front wheel suspension sets new measures... Two triangular suspension arms support a fork, whose form is ideally suited to resist the bending forces that tend to deflect it. The two ball-joints, which tie the fork to the suspension arms, (A-arms) create the steering axis. The two steering head bearings, which tie the steering head to the fork, define the steering head axis. a scissors-link, with two triangular a-arms linked at their common end, serves to transmit the steering inputs to the fork itself. It moves with the suspension movements of the front wheel. A coil-over shock unit supports the lower suspension A-arm at the bottom and is anchored to the frame at the top. What advantages does this system, invented by the Englishman Norman Hossack in the '80s, offer us today? In comparison to a contemporary telescopic fork it allows a more compact frame structure, lacking a conventional steering head through which immense bending forces act on the frame through the "lever" of the tele-fork. A substructure carries only the bearing supports for the handlebar, while the two A-arms guide the forces acting on the front end directly into the chassis. A further advantage: better responsiveness of the front wheel on small bumps, since the friction between fork tube and slider common to all tele-forks is absent. Also important: The elimination of front end dive under braking makes for the optimal use of the ABS, and thedesign offers nearly constant geometry of the chassis throughout the entire range of suspension travel. In conclusion, the two-armed front wheel support offers yet another advantage over the Telelever. The Telelever, by all accounts, suffers from a significant disadvantage. As the suspension extends, trail is reduced and the steering head angle steepens, which can lead to instability at high speeds. No problem for Boxers and Tourers (...not fast enough...KP) but for a superfast machine definitely problematic. The new single-sided rear swingarm connects itself through a progressive rising-rate linkage to the frame. The compact motor, with the transmission shafts stacked one atop the other, has made enough room for this system. The torque of the driveshaft is resisted now by a link above the swingarm/driveshaft housing. As with the recently revealed R 1200 GS the pivot point of the final drive on the driveshaft housing lies under the driveshaft's path, which is quite unusual.
The New Four Cylinder
Finally the BMW motor wizards are permitted to break with tradition! Now our Bavarian colleagues are installing a four cylinder engine across the frame, and integrating the transmission into the crankcase housing. This architecture produces a shorter and lighter motor. And in order to maintain as low an overall height as possible, the cylinders are leaning forward at a 60 degree angle. the extremely short-stroke four cylinder motor spins to 11,500 rpms in its 1200cc version, which leads us to conclude that the power output will be from 160 to 170 PS. A ram-air system provides fresh intake air to the huge airfilter/airbox, which will provide a small pressure boost to the intake air at very high speeds. A new fuel injection/engine management system controls the motor, naturally with three-way cat and secondary air injection as well.
The camshaft drive is most interesting. A timing chain drives the exhaust cam on the right side of the engine, while straight-cut timing gears set the intake cam spinning. Valve actuation is done by a sort of rocker arm. The crankshaft, with the right crankshaft webused as the primary gear, turns forwards, and drives the transmission input shaft together with the clutch. Daigonally underneath, near the swingarm axis, is the transmission output shaft, so that the driveshaft, with two universal joints, can operate with very little shaft reaction. The alternator and the starter are also on top of the transmission, keeping the whole motor very narrow. The new K-BMW represents a real technology offensive. Therefore she should not, perhaps, still be called a "K". The new name remains to this time still a secret.
By Michael Pfeiffer
Drawings by Stefan Kraft
Photos by Motorrad staff
Translated by Kari Prager. This is an informal translation, done for your fun and amusement. Any inaccuracies are the fault of the translator. You may use this material in any non-commercial way.