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GS with BMW in-line six

GS con sei cilindri in linea BMW

In the BMW portfolio, there is a suitable motorcycle for every purpose. However, this creation by Dutch specialist Nico Bakker shows that there may still be gaps in such a comprehensive range.

BMW model strategists usually build various versions around each of their engines to suit almost any taste. However, since its appearance in 2011, the fabulous straight six has only been available in the K 1600 GT, GTL and Bagger, all fully enclosed supertourers. The Custom Six, a naked bike shown by BMW itself at EICMA in 2009, also did not go into production.

K 1600 GT impossible to fold

Dutchman Willem Heijboer also asked himself this question. Willem is an entrepreneur and a thoroughbred biker who always goes to his clients or his meetings on motorcycles. A few years ago, he was still driving an R 1200 GS, but due to the improved comfort, the two-wheeled Dutchman bought the travel giant K 1600 GT with its powerful straight six. While driving, however, Willem scraped the fairing engine covers. The not too high lean angle annoyed the racing entrepreneur so much that he came up with the idea of combining the powerful engine of the K 1600 GT with a GS-type chassis. Heijboer himself would not have been able to make this wish come true, however, so he knocked on Nico Bakker's door.

Frame and chassis

The Dutch frame guru is considered one of the best frame designers in the world and has been building special racing solutions or - as in this case - at the request of private customers for 44 years. Nico has already developed more than 1,000 different tubular frames, from small 50cc crossers to GP rockets. Despite this wealth of knowledge, however, he was aware that Willem's plan to conjure up a GS version from the K 1600 GT was not going to be easy to accomplish. Nonetheless, Nico naturally accepted the challenge. The end result is a truly impressive bike, the K 1600 GS, aptly named "Mammut".

The six-cylinder engine is now encased in a chrome-moly steel tube frame. This allowed Nico to keep the frame light - while maintaining high stiffness. To make the bike manageable, Nico transplanted the engine, which weighs a whopping 102.6 kilograms, quite high in the tubular mesh, thus changing the center of gravity. It also lengthened the 17mm wheelbase to 1635mm, but refined the geometry. In place of the telelever, a fully adjustable USD fork from WP Suspension keeps the travel steamer on course. This was later modified by HK Suspension and adapted to the special needs of the Mammut-GS. As a treat, the suspension specialists from HK have adapted the standard BMW ESA semi-active suspension into a WP suspension strut. The bike also has Kineo spoked wheels to give it the right GS look.

39 liter tank and Aprilia radiator

To accommodate the shaft drive, the pair of wheels was made specifically for this bike. Pirelli Scorpion Trail II tires give contact with the road. Since Willem needs a lot of luggage on his business trips, Bakker has fitted the bag system of an R 1200 GS to his frame construction. It also doesn't have to refuel often, because the original 24-liter fuel barrel has been replaced by a special construction with a gigantic 39-liter capacity. To ensure that the engine does not die of thermal exhaustion over a total of 25,000 kilometers per year, an Aprilia RSV 1000 radiator provides the right thermals. Akrapovic's Slovenian exhaust experts contributed a specially made stainless steel exhaust system, which was tuned to the engine by an adapted ECU. The K 1600 GS weighs a total of 310 kilograms, with a full tank. This is nine kilograms less than a normal BMW K 1600 GT. But enough with the facts and figures. Such a special bike must and should be ridden, so put your helmet on and get in the saddle!

Smoother and silky torque curve

The Bakker creation places the rider in an upright and very relaxed riding position, made possible by the relatively low footpegs and high handlebar positioned far back. In addition, the bike offers enough space, even for tall riders. The seat height is 820mm, but even a tall rider can only touch the ground with his toes because the bike is extremely wide due to the huge tank. The front of a Boxer-GS with its high windshield protects against rain and wind.

When you push the start button, the 1,649-cubic six-cylinder wakes up with a low, muffled sound. The complete Akrapovic system is only a little louder than the original, but it provides the appropriate soundscape for such a giant engine. Even at idle, you can feel the lightning-fast power when playing with the clutch. If you then open the throttle, the six-cylinder engine offers a smooth and silky torque curve. It's easy to get through the city in sixth gear without the engine running rough. The three different riding modes (Rain, Road, Dynamic) are perfectly tuned and give the mammoth's heart a moderate or completely sporty pace. Under full load, the 160-horsepower engine turns smoothly and at the same time powerfully towards the limiter with no noticeable loss, while the gears slide into place with just light pressure on the lever and little pull on the clutch.

Surprisingly good handling

Surprisingly good management and! Despite its impressive size and heavy weight, the K 1600 GS can be effortlessly rolled through tight curves without letting sweat drop to the forehead. The bike also masters U-turns in city traffic with a composure that is exceptional in this segment. As soon as you leave the city and head for the countryside, the Bakker-GS impresses with its rich road holding and high stability in long, fast corners. The Brembo brakes grip firmly and the ABS adjusts gently, as is typical for BMW..


After an impressive lap, I wonder why BMW itself hasn't yet come up with the idea of crossing a K 1600 GT with the GS. Either way, the scratched engine fairings are definitely history for Willem Heijboer. And Nico Bakker says he could always build another K 1600 GS like this one. Cost About 50,000 euros..

Original article

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