Aussie 'CYCLE TORQUE' article

[Trevor Rossack]

Here are some more interesting insights and the all important ride impression of the K200S from the August issue of 'Cycle Torque'.


BMW'S AUTOBAHN EATER
BMW's new road blaster is a glimpse into the future of the German Manufacturer' fours....
launch report by Nigel Paterson


167HP. Under 250kg, ready to roll. New front suspension, never before used in a production motorcycle. Electronically adjustable suspension. Aerodynamics to help the massive power output push the machine to around 300km/h.

Not very many years ago it would have been unimaginable for such a machine to come from BMW, once the most conservative of the major manufacturers and one which refused for decades to get into power wars with the mighty Japanese companies.

But times change and now we have an awesome new machine which can compete head to head with the likes of Suzuki's Hayabusa, Honda's Super Blackbird and even Kawasaki's ZX-12R. And like these bikes, the K1200S is simply a sports machine - not a supersport/race replica - BMW have successfully made the bike comfortable and suitable for pillion passengers.

The bike is desigened to be comfortable, fast, stable and safe on the speed limit-free autobahns, where 180km/h in the fast lane can get you run over.

This is just the second generation of BMW four-cyclinder motorcycle. The first was the original K100, which debuted over two decades ago and, despite it being the first BMW four-pot bike, offering fuel injection and many other innovations, BMW claim the K1200S offers more.

I know it has the potential to be the best bike in its class. The engine is smooth and linear, spins up like no BMW before it and the ergonomics are an excellent compromise between all-day comfort and Sporting prowess.

THE ENGINE
To build the K100S, BMW had to thow out it's earlier designs. To get the right amount of power and torque, it had to have four cylinders, but the earlier flat-four had to go because it would have made the bike too long.

Instead, the engine is a transverse four. The basics make the engine sound conventional - a fuel injected DOHC four-valve, transverse four-cylinder with liquid cooling. But it's the details which make the K1200S unusual, innovations like having the cylinders cranked forward 55 degrees, a dry sump and cylinder head technology carried over from Formula One racing. Having only the exhaust cam chain driven from the crankshaft, the inlet cam being gear driven from the exhaust cam, to improve valve timing (due to less freeplay) and keep the size of the head as small as possible.

The 16-valves are mounted at extreme angles - 10 degrees for the inlet and 11 degrees for the exhaust, which helps keep the combustion chamber compact. This, in conjuntion with the engine management system including knock control, allows the ultra-high compression ratio of 13:1 despite the bike's ability to run on pump fuel.

The clutch is a wet multiplate unit driving a cassette-style transmission which is stacked to keep it short. The six-speed transmission ends in shaft drive to the rear wheel, making this the only contender in the class without chain drive.

The clutch on my bike became grabby and difficult to use at the end of the day. This was, however, probably caused by the photo shoot, which saw us running our bikes over the same piece of road many times. I also want to point out the bikes we we riding were part of the first batch of K1200S machines, and are therefore really just specials developed so the press could write about the bikes before the sales begin.

All this adds up to a compact motor and gearbox which keeps the centre of gravity low (because of the dry sump), with much of the weight forward near the front wheel ( because of the cylinder angle).

Fuel is supplied from the 19-litre plastic tank through a full sequential injection system controlled by a sophisticated engine menagement system. The 10-litre airbox sits directly above the cylinder head with the air intake being below the headlight, giving a ram-air effect.

Exhausts exit through a catalyser-equipped stainless steel 4-2-1 system, which at 10.4kg, is claimed to be the lightest in the world.

Providing the electrical energy around the machine is BMW's Single Wire System (SWS), first intrduced on the R1200GS earlier this year. Using CAN-bus (Controller Area Network ) technology, SWS incorporates all the electrcal information of the bike through a single wire, hence the name (although there's actually two, because the system features a back-up).

The advantages include much less weight, easier diagnostics and a high level of robustness.

CHASSIS AND BRAKES
Fully robot welded, the twin-beam alloy frame of the K1200S is very unusual. There's no conventional head beacuse of the Hossack-style front suspension and the extreme angle of the cylinder bank means the design of the frame wasn't compromised by having to go over or around the cylinder bank. This allowed BMW to keep the frame narrow, as the beams needed only to be wide enough for the airbox and fuel tank. The beams meet at the front where the suspension mounts.

The main frame beams run relatively flat to the rear of the tansmission, where they drop almost straight down to the swingarm pivot. The engine hangs from the chassis; there are no lower downtubes.

BMW's servo-assisted EVO brakes are fitted to the K1200S, along with the partially integrated braking system and ABS. The foot pedal acts just on the rear brake, but the hand lever applies pressure to both. Customers will be able to order a K1200S without ABS, but the bike will be built specifically for you in Germany, so the waiting time might be long in Australia.

DUOLEVER AND PARALEVER
Duolever is BMW's name for its innovative front suspension system. No front forks or the old Telelever system for the K1200S.

The basic idea for the system dates back to the 1980s and British inventor Norman Hossack - two longitudinal arms in a parallelogram arrangement, very similar to wishbone car suspension, except vertical rather than horizontal.

In BMW's adaptation of Hossack's design, there's a large alloy fork wrapped around the wheel. The two nearly parallel arms join the wishbone to the frame, with the wheel movement controled by a spring/damper unit similar to a rear shock. Ball pivots allow the wishbone to turn, giving you steering.

Connecting the wishbone to the handlebars is a hinge, which simply closes as the wishbone moves up.

The beauty of the system is rake ,trail and wheelbase are effectively unchanged no matter where in the stroke the suspension is. It is also lighter than a comparable Telelever system by about ten per cent.

The rear suspension and shaft drive unit are similar to that of the R1200GS, although suitably modified for the high power output, weight and suspension travel of the K1200S.

ESA - Electronic Suspension Adjustment - is offered as an optional extra. Using buttons on the handlebars (but only at standstill) the rider can select between 'solo', 'solo with luggage' and 'passenger and luggage' in combination with 'comfort', 'normal' and 'sports', giving a total of nine different settings.

Both spring preload (via an electric motor) and damping in both directions is adjusted in the rear shock (using step motors in the suspension units), while only the compression damping at the front is affected by ESA.

THE RIDE
The international bike launch gave us just one day to play, but I've come away from the K1200S believing this will be a groundbreaking model for both BMW and the industry.

The design has kept the weight of the machine very low, which makes it very easy to flick around. The Duolever front suspension allows the rider to brake much deeper into corners with little dive and almost no propensity for the bike to want to stand up in the corner. It just slows down, holding its line. Bumpy corners seemed to be handled better than most telescopic forks, but given the nature of German roads, it's still unknown how the bike will cope with the imperfect Australian bitumen. The front tyre was especially developed for the machine.

Perfromance is outsanding. This is a very fast motorcycle. I saw an indicated 260km/h on the large analog speedo (BMW policy is not to use digital speedos), and it got there very quickly indeed.

It's also remarkably comfortable. Sure, I'm quite tall so I had to put in an effort in to get down and under the influence of the fairing, but once there it was nice and buffet-free.

My only complaints were a few vibrations through the footpegs, handlebars and tank.

All up, BMW has built a really, really great bike. It feels very fast, very safe and goes around corners nicely. Although BMW hasn't announced a price as yet, expect it to be in the region of $25,000