BMW 450 flies to Oz

BMW has flown a prototype 450 enduro racer out to Australia to join the Summer show circuit.

The machine has been doing demonstration laps at road race circuits in Europe over the last six months, and has competed in selected off-road events, but this is the first time it has been seen locally.

"The 450cc Sports Enduro prototype racer is in Australia ahead of any official announcement to stimulate interest in our off-road racing exploits, and to gauge reaction to a product such as this," said Cameron Cuthill, General Manager, BMW Motorrad Australia and New Zealand.

"Concept cars are prevalent in the automotive industry, but they rarely turn a wheel, and never in anger. At BMW Motorrad we are confident in our prototype engineering and we learn plenty from competition at the highest level.

"This is why our prototype machine has been wearing numbers on its flanks for the past six months and has been enjoying a very robust shake-down in the hands of multiple race champions in the white-hot heat of international competition. The results have been superb," Cameron said.

"We are delighted BMW Motorrad in Germany has chosen to give Australian motorcycle fans the chance to examine this 450cc Sports Enduro prototype up close in Melbourne this week.

"We have flown the machine out from Germany at some cost to give Australians a glimpse of what could be," he said.

There are no firm plans to build the machine at this stage, though if it did go aherad it would be the smallest capacity motorcycle the company has built in several decades.

Meanwhile the firm has unveiled a road version of its Boxer twin R1200-series endurance racer, called the HP2 Sport. Expected here next year, the machine claims 133 horses from a double-overhead cam version of the powerplant. See our main story this week for more details.

Here is BMW’s tech brief for the 450:
This competition prototype has been designed based on these ideas. The frame forms a composite triangle made of high-precision premium steel tubing actually developed for crash structures and rarely used in motorcycle construction.

Two arched tubes lead from the steering head via the engine to the swing arm pivot. The swing arm pivot is supported via the shortest possible distance by the steering head, pointing at an angle towards the front via two straight tubes.

This construction requires minimum use of material and thus allows a hitherto unequalled relationship between rigidity and weight. This frame layout is only possible in conjunction with the clutch position on the crankshaft as mentioned above and a cylinder which is tilted far forward. The rear frame is formed by lightweight square profiles made of light alloy which are bolted to the main frame.

The coaxial mounting of the swing arm and the chain pinion had to be solved in a practical manner. In the current design, the swing arm pivot mounted on the frame leads through the hollow gearbox output which bears the drive pinion. To change the pinion, the motorcycle is jacked up, the swing arm pivot is pulled out and the swing arm with mounted wheel is folded backwards. A practised mechanic can do it in 15 minutes.

The other chassis elements are conventional and are in keeping with the high standard of the class. The front wheel control is provided by an adjustable upside-down fork by Marzocchi with a spring travel of 300 mm. Suspension and damping of the rear wheel is taken care of by a directly linked, progressively operating Öhlins suspension strut with a spring travel of 320 mm. Set at a angle, it is supported directly by the rigid main frame.

The engine of the competition prototype is 450cc high-performance single cylinder four-stroke engine designed by BMW with two upper camshafts and dry sump lubrication. A special feature which is unique in this class is the fuel injection and oxygen sensor regulation. The position of the cylinder, tilted far forwards, enables virtually straight intake air ducting into the large-volume airbox positioned above the engine. This provides excellent conditions for optimum engine performance tuning. This favourable overall arrangement was made possibly by the fuel tank position below the rider's seat, familiar from the existing BMW single-cylinder models, with all its advantages in terms of the centre of gravity.

Another unique feature is the position of the clutch: it is located on the right crankshaft end and was thus given extremely compact dimensions since it rotates with the engine due to a lack of a speed-reduction ratio of the primary drive: it therefore has to transfer a lower level of torque. An intermediate shaft with integrated ventilation function transfers the power from the crankshaft to the gearbox. An electric start is obligatory.

The chain drive to the rear makes do without additional tensioning devices and channels due to the fact that chain sag is barely necessary any longer and the chain retains a constant length - another weight-saving factor. The load-alteration effect on the powertrain is reduced, chain stress is reduced, and final drive longevity is greatly increased.

The performance figures of the engine are at competitor level, though further details will be revealed at a later stage. This also applies to the total vehicle weight - even the first concept vehicle achieved levels in the range of the established representatives of this motorcycle class.

(Pics: BMW stunt rider Chris Pfeiffer at speed; MX veteran Joel Smets tries a water crossing.) See: BMW.com.au