> 6 cylinders in line, 1649 cm3, 175 Nm, 310 kg fully loaded, 39 liter tank, tubular frame...

BMW engineers generally build different versions for almost all tastes around each of their engines. However, since its introduction in 2011, the famous straight-six engine has only been available on the K 1600 GT, GTL and Bagger, all of which are fully faired super tourers. The Custom Six, a naked motorcycle, which BMW presented at EICMA in 2009, also did not enter production. Why actually?
The Dutchman Willem Heijboer also asked himself the same question. Willem is an entrepreneur and a thoroughbred biker, he always goes to his clients or appointments by motorbike. A few years ago he was still on the road on an R 1200 GS, but the Dutchman then bought a K 1600 GT with a powerful straight six-cylinder engine. However, the businessman quickly encountered limited ground clearance and a lean angle that could not compete with his maxi-trail.
So he had the idea of ​​combining the powerful engine of the K 1600 GT with a GS-type chassis. Willem Heijboer himself could not have implemented this project, so he knocked on Nico Bakker's door.
The Dutch guru is considered one of the best frame designers in the world. Nico has been building special solutions for racing or - as in this case - for private customers, for 44 years. Despite this experience, he was aware that Willem's project would not be easy to implement. Nevertheless, Nico accepted the challenge. What ultimately resulted was a truly impressive motorcycle, the K 1600 GS, aptly named "Mammoth".
The six-cylinder block is now inserted into a frame made of chrome-molybdenum steel tubes. This allowed Nico to preserve the lightness of the original frame while maintaining great rigidity. To make the bike easy to handle, Nico transplanted the 102.6 kg engine quite high into the frame, changing the center of gravity. The wheelbase has gained 17 mm to stand at 1635 mm. In place of the Telelever, a WP inverted fork, modified by HK Suspension, was adapted to the specific needs of the Mammoth.
In order to accommodate the cardan transmission, the 6-inch wide rear wheel was specially designed for this motorcycle. For his business trips, Willem wanted to integrate the rigid luggage of an R 1200 GS. In addition, the fuel tank of the BMW K 1600 GT, with a capacity of 24 liters, has been replaced by a tailor-made 39 liter model, allowing a good range of 6 to 700 kilometers. In the end, the fully loaded weight comes to 310 kg. This is 9 kg less than the K 1600 GT.
Nico Bakker's creation places the rider in an upright and very relaxed riding position, made possible by relatively low footrests and high-positioned handlebars. In addition, the motorcycle offers enough space even for a tall rider. The seat height is 820 mm, which is reasonable for a trail, but the bike is very wide due to its large tank. The high windshield of a GS protects against rain and wind.
Nico Bakker opted for 19-inch spoke wheels at the front and 17-inch at the rear shod with Pirelli Scorpion Trail II in 120/70R19 and 190/55R17. The liquid cooling radiator fitted to the Mammoth comes from an Aprilia RSV1000. The Akrapovic 6-2 exhaust with its two carbon silencers from the Slovenian factory was also specially designed for the K 1600 GS and fulfilled Willem's wish to have a slightly better sound than the BMW standard, not noisy, but just a little more exciting.

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The engine starts to sing as soon as you press the start button then comes to life and settles into an idle of 950 rpm. Despite its long wheelbase, the Mammoth proves to be a real fan of small spaces. It provides very balanced driving at low speeds in town. The engine is so smooth and flexible that it is possible to let it run at 1500 rpm in the last gear and accelerate sharply, without jerks, up to the 8500 rpm red zone. The handling is very safe in all circumstances. At low speeds, the motorcycle is bulky, but well balanced, allowing U-turns or maneuvers in town with confidence.
Soft, elegant, sporty, sophisticated, we can't help but think that BMW should market such a model. It wouldn't be the first time that Nico Bakker would take care of product development for them!
In the meantime, if you want to entrust Nico with the transformation of your K 1600 GT into a GS, count on six months of work and a budget of around 50,000 euros.