When it comes to customising older BMW motorcycles the R series airheads are the most popular weapon of choice. Fuss-free naked styling, an accomodating chassis and the iconic boxer engine configuration are all part of the appeal. But popularity has its drawbacks. R series bikes are getting harder to source and more expensive to acquire so more and more builders are testing the waters with other classic Motorrad models. This was the exact scenario German workshop Kraftrad Noeda found themselves in when looking to expand their BMW build portfolio.
“After we had already converted some BMW boxers, we wanted to try a K100,” says Kraftrad Noeda’s Martin Tzscheuschner. Commonly referred to as the ‘Flying Brick’ the BMW K100 is a bit of an oddball in the Bavarian history books. Produced between 1988 and 1992 it earned its unusual nickname due to the appearance of its inline 4 engine. The engine was developed to tackle stricter emission laws and to compete with the liquid-cooled 4 cylinder bikes coming out of Japan. Despite a relatively short production run the K100 achieved it’s intended purposed and helped pave the way for several other BMW engine, suspension and braking developments.
For this project, Kraftrad acquired a BMW K100 RS from 1992. All K series bikes came with dual front brakes and a lightweight alloy fuel tank but the sportier RS benefitted from taller gears. The late-model K100s also featured a 4 valve per head design developed for the radical, autobahn busting, BMW K1. The big question though was how to turn a fully-faired, brick-like behemoth into a svelte cafe racer.
After stripping the K100 RS down to its bare essentials a plan was hatched to create a bike that celebrated the brick’s eccentric nickname. To do this they took inspiration from vintage aeronautics. The concept revolved around exposing the bikes aluminium components, adding a few more of their own and finishing the bike using aircraft-inspired livery. But first, they had to reduce the bikes visual weight.
Kraftrad kicked things off with a few modifications to the K100 RS chassis. A trimmed-down subframe frame tightens things up in the rear and converts the bike to a single-seater. The triangle of the frame has been cleared out by relocating the electrics and stashing them, along with a lithium battery, beneath the bike’s new rear cowl. The radiators expansion tank has also been moved out of sight by placing it in front of the air filter housing. Then, since there was no way of reducing the size of the engine, Kraftrad came up with a solution to disguise its less appealing aspects. Using contrasting paint finishes they’ve drawn attention to Flying Bricks iconic engine cases and disguised everything else using a low sheen black paint. Surprisingly the treatment is highly effective with the silver accents of the bike demanding all the attention.
The bike has also received some bespoke bodywork and some off the shelf upgrades to declutter things even further. Up front there’s a short custom made fender. A custom fairing houses the reg/rec along with an asymmetrically mounted headlight. The rest of the bike’s lighting is all LED. Tiny Kellermann Atto indicators sit either side of the front cowl and tail and a retro-styled brake light is recessed into the rear. Then to keep the rear free from clutter a custom exhaust system snakes its way around the belly of the brick.
“We tried to incorporate many details that are reminiscent of aeroplanes,” says Martin. To do this the Kraftrad team has created some truly unique additions to this BMW K100 RS cafe racer. For starters, the cockpit of the bike is a comprehensive collection of dials, warning lights and switches arranged on a custom panel. They offer information such as revs, temperature and the fuel level, but the actual speed is displayed elsewhere. Mounted to the front of the fuel tank is an additional panel featuring a vertically mounted Motogadget Motoscope mini digital gauge. Moving rearward there’s an aviation-style filler cap on the bare alloy tank. The saddle has been upholstered similar to vintage fighter plane seats and most of the bodywork is secured with fasteners that mimic aircraft rivets.
If you’re going to go with a theme you may as well go all in and Kraftrad Noeda hasn’t pulled any punches. Taking full advantage of the BMW K100 RS single-sided swingarm they added a “propeller spinner” to the centre of the rear wheel. All of the aluminium components were glass bead blasted raw and the frame is finished using a vintage airforce inspired green. The icing on the cake though is the extensive aeronautical symbols and insignia covering the bodywork that offer a wide range of amusing, albeit redundant information.
Custom motorcycles like this have a tendency to be polarising and we’re sure there will be plenty of Flying Brick fans with something to say about this one. But if you ask us, we think this it’s Sierra Hotel.