Elegance meets conceptual design in Auto Fabrica’s latest café racer build—a BMW K100 with a monocoque body finished in Liquid Orange.
The English workshop Auto Fabrica is renowned for building sophisticated custom motorcycles with a conceptual edge. But what’s truly remarkable is how they manage to apply that philosophy to almost any type of machine. We’ve seen them tackle everything from the evergreen Yamaha XS650 to the modern BMW G450X enduro.
Now, they’ve worked their magic on perhaps the ugliest duckling of all—the BMW K100.
The brothers behind Auto Fabrica, Bujar and Gaz Muharremi, didn’t seek out the infamous Flying Brick as a donor for their latest café racer project. The commission came from a client who already owned the bike, along with a more suave Honda CB750. Both bikes were dropped off at AF’s workshop with a mandate to turn them into a pair of unique custom builds.
“We had never built on either platform before,” Bujar tells us. “The BMW K100 has been customized countless times, but we didn’t want to create a run-of-the-mill K100. That pushed us into designing something far more radical, sculptural, and refined—something that still felt unmistakably AF.”
“The donor K100 arrived complete, but tired. Its original form didn’t inspire us visually, but the flat-four engine certainly did. It’s a very architectural engine—horizontal, modular, almost monolithic—so that informed the entire direction of the build.”
“The design language came from architecture and from BMW’s most interesting concept work. The flat-four layout encouraged a bold, angular, blocky aesthetic, balanced by refinement in the lines and proportions. I looked at BMW concept cars like the Skytop, Gina, the 328 Hommage, and the M1 Hommage. They all share tension and sculptural minimalism, which felt perfect for this project.”
The influences that Bujar cites are most evident in the K100’s monocoque body. Sculpted from carbon fiber, it embodies neo-futuristic concept car themes while conveying a sense of fluidity. The multi-faceted design rewards closer inspection, too, revealing fresh details from each angle.
Finished in Liquid Orange (a color pulled from the BMW M1 Hommage), the bodywork covers a handmade 12-liter [3.2-gallon] aluminum fuel cell. Replacing the stock reservoir was no mean feat—AF had to build a custom setup to house the fuel pump and filter externally.
The bodywork is topped off with a pop-up gas cap and an Alcantara saddle. Lower down, a custom subframe supports the tail end, while 3D-printed radiator shrouds create a segue between the vivid paintwork and the K100’s myriad matte black parts.
The front fender is another 3D-printed piece, as is the scooped ‘intake’ panel on the right-hand side of the bike. AF retained the first stage of the stock airbox assembly, but modified it to work with a single oversized pod filter.
Wedged between the frame and rear wheel is another 3D-printed part; a box for the ECU and battery that doubles up as a rear fender. “I wanted the visual language of the engine—the horizontal layering and block-like geometry—to continue seamlessly into the tail section,” explains Bujar.
“Textures were important. The intakes, coil cover, and both fenders use a soft-touch matte black finish that contrasts beautifully with the bead-blasted and matte black engine surfaces.”
Sitting alongside the fender-slash-box is a cantilevered rear suspension system of AF’s own design. Its linkages were all CNC-machined in-house, while its horizontally-mounted shock is a custom-built unit from Hagon. “This suspension layout completely opened up the visual space around the swingarm area, while giving the bike a modern, progressive rear-end feel,” says Bujar.
Up front, AF installed a set of upside-down forks from a Ducati 999 with custom yokes. The 17-inch rear wheel is a BMW R1150GS item, while the front wheel uses a 17-inch R80G/S rear rim laced to an R1150GS hub. Brembo brake calipers do duty at both ends.
The K100’s checklist also included an engine rebuild and refinish, plus a full rewire with Motogadget goodies—including a keyless ignition and discreet digital speedo. The latter is mounted in a deep recess atop the custom-made headlight nacelle, which also houses the front turn signals. Clip-ons adorn the cockpit, matched to BSK SpeedWorks rear-set foot controls.
The underslung four-into-one stainless steel exhaust system is another one-off part. “It sounds mechanical and crisp,” Bujar confirms. “It’s surprisingly not as loud as expected, but it suits the bike perfectly.”
Out back, the K100’s new tail tapers into a custom taillight assembly—another wonderfully thought-out detail. Using a 3D-printed louvered housing, it’s a vague nod to the grills on vintage BMW automobiles.
Designated ‘Type 25,’ Auto Fabrica’s custom BMW K100 continues the workshop’s fine tradition of pushing the envelope. “Type 25 fits into a new chapter for us—one that embraces more architectural, concept-car-inspired thinking,” adds Bujar.
“It’s recognizably Auto Fabrica in its refinement and surfacing, but pushes the language further: more monolithic, more sculptural, more intentional.”
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