Upgrading your suspension and brakes is a hassle-free way to eke more handling performance out of your motorcycle. But if you have the time and money, why not go the whole hog? This Honda CB900F from HB-Custom in Germany sports several upgraded parts—but its biggest drawcard is its race-bred Rau frame.
If you’re not familiar, Manfred Rau was a German frame builder who started making performance motorcycle frames in 1972. His designs took cues from the work of Egli and Bimota, with a focus on Japanese engines.
Needless to say, Rau frames aren’t easy to come by… which is exactly why Holger Breuer (the ‘HB’ in HB-Custom) had to find one for his latest project. “The client is a very good friend of mine and it’s the second bike that we’ve built together,” he tells us. “The goal was to build something really special with more or less no budget restrictions.”
“The first bike that I built for him was a BMW—but the whole custom BMW thing has become kind of boring. The goal was to follow a new direction; a four-cylinder engine instead of a boxer, a Honda instead of a BMW, and a very unique frame.”
Some deft hunting by Holger produced a 1977 Rau frame and a Honda CB900F of unknown vintage. The engine was yanked out of the CB and rebuilt to the tune of 1,062 cc. Peek inside, and you’ll find rebored cylinders and a set of forged Mahle pistons.
This Rau Honda CB900F also benefits from a set of Mikuni RS36 carbs, fed by a custom-made carbon fiber airbox to comply with Germany’s stringent regulations. Without any cam- or crankshaft fettling, it now pushes out close to 100 hp. A digital ignition and hydraulic clutch add modern reliability.
Since the Rau frame that was sourced for this project was designed for the CB900F motor, bolting the latter into the former was a mere formality. To complete the rolling chassis, Holger added the forks and yokes from a Suzuki GSX-R1000 K7 up front and installed a Wilbers shock at the back. A Wilbers steering damper was fitted too, for extra front-end stability.
The stunning 17” wheels are custom-built items from the German wheel specialists PVM. They’re wrapped in Pirelli Diablo Supercorsa tires and stopped by an assortment of Yamaha R1 and R6 braking components.
Holger only used the Honda CB900F’s engine, which meant that he had to create everything else from scratch. For the bodywork, he manipulated sheets of aluminum to form a new fairing, fuel tank, and humped tail section. The bike’s new lines borrow ideas from both café racer and vintage race bike aesthetics, with a few hard edges to echo the CB’s DNA.
A generous cutout on the right side of the fuel tank offers a view of the Rau frame’s distinctive backbone. Take a closer look, and you’ll also spot a handmade ‘fuel gauge.’
The sleek fairing wears an MRA windshield and hosts an LED headlight from Koso. The taillight’s from Highsider, and the turn signals are Kellermann items. Tucked away in the cockpit are a Motogadget speedo and RFID ignition receiver, with Gilles Tooling clip-ons, Magura levers, and Highsider switches.
Gilles Tooling rear-set foot pegs are mounted lower down, as are numerous carbon fiber and drilled parts. A custom license plate bracket sits out back, while a burly four-into-one exhaust from Schüle adds the final touch.
Wrapped in a dark teal livery with subtle black graphics, HB-Custom’s Rau Honda CB900F has a subdued look that belies just how wild it is. We could stare at it for ours—and we can only imagine how glorious it must sound at full tilt.
HB-Custom | Instagram | Images by Emayat Wahab
