In 1982, BMW introduced their first liquid-cooled four-cylinder motorcycle engine in the K100 — a quantum leap forward from the air-cooled flat-twin “airheads” for which they were known. Uniquely, the new engine was mounted on its side in the motorcycle’s frame, so that the crankshaft was on the right side of the bike and the cylinder head on the left, which quickly led to the new motorcycle’s nickname: “Flying Brick.”
“The chefs in Bavaria gathered in the kitchen and whipped up a real treat—a liquid-cooled four, laid on its side and clothed in swoopy bodywork—that still tastes good today, and borders on becoming a modern classic as well.” —MCN
The 987cc engine, rated at 90 horsepower, boasted a “Compact Drive System” shaft-drive and Bosch Jetronic fuel injection similar to the systems used in the company’s automobiles. The “Flying Brick” could reach at top speed of 137 mph and managed to give BMW slightly more performance-oriented image. In fact, an all-but-showroom-stock K100RS came in 8th in the 1984 Production TT.
“The K100 claimed 90bhp (less than the air-cooled Japanese superbikes of the day or the GPz900R/GSX-R750 a year later) at relatively low revs, was easy to use, with accessible power and a real world top speed in a low state of tune that would keep it reliable for hundreds of thousands of miles.” —Bennetts
Interestingly, due to the unique engine configuration, the K100 — along with its three-cylinder sibling, the K75 — is known to smoke at startup if left on the side-stand for too long, as oil seeps past the rings. Many owners park their bikes on the center stand to avoid this, or else tilt the bike to the right for 10-15 seconds after shutting it down, then placing it on the side stand.
While the K100 was a modest sales success, surely no one at BMW Motorrad guessed the K100 would come surging back into popularity more than three decades after its introduction. But in recent years, the bike has become a favorite donor for cafe racer builders all over the world. The unique engine layout and angular lines make a fitting canvas for a cafe build, and the Brick’s 90-hp inline four has plenty of power to back up the performance aesthetic.
Below are some of our favorite K100 cafe racers we’ve featured here on BikeBound.com.
BMW K100 “Apollo” by Ruby Cafe-The K100 was developed during a time when BMW felt the need to create a modern, liquid-cooled machine that could compete with the inline fours coming out of Japan. The design concept was unique in […]
Alloy Racer: BMW K100 Custom by Basan Metalworks-For Sale: BMW K100 cafe racer from Basan Metalworks! The BMW K100 “Flying Brick,” built from 1982-1992, has become an unexpected darling of contemporary custom culture. This ’80s cruise missile challenges builders to design around […]
Blue Moon: BMW K100 Café Racer by RW Motorcycles-The BMW K100 seems to be experiencing a renaissance in the custom world. The 90-horsepower, fuel-injected engine offers good punch, and the “Flying Brick” is known to be rock-solid during high-speed cruising. Still, it’s safe […]
“Hurricane”: BMW Flying Brick Café Racer-The BMW K100 “Flying Brick” represented a significant design leap for BMW Motorrad, who’d long been known for their flat-twin “airhead” engine design. The K100, in contrast, was a fuel-injected, liquid-cooled inline four laid flat […]
BMW K100 “Shahin” by Mehdi Barakchian-An ’87 Flying Brick dragged “kicking and screaming” into 2019… The BMW K100, introduced in 1982, benefited from the company’s many years of experience building liquid-cooled, overhead cam, inline automobile engines. The fuel-injected, 95-hp engine was […]
BMW K100 Custom by De Angelis Elaborazioni-The BMW K100 may seem an unlikely candidate for customization, but builders have discovered the beauty in the “Flying Brick.” The heavy block of engine, laid flat in the frame, keeps the center of gravity […]
BMW K100 Bobber: “Mira”-Trevor Ryan Ditson of Prescott, Arizona, spent his young years in the garage, helping his father build choppers and his grandfather who was into drag racing. After two decades as a chef, he decided to […]
BMW K100 Tracker by Overbold Motor Co.-Barcelona has become a hotbed for custom bikes, largely thanks to builders like Overbold Motor Co., whose CB750 Nighthawk cafe racer we previously featured. Now the crew is back with another stunner: this time a […]
BMW K100 Cafe Racer by Weston Customs-Who would have guessed that the BMW’s first four-cylinder motorcycle, the K100 “Flying Brick,” would be reborn in the hands of custom builders 35 years after its introduction? We were lucky enough to spy this […]
BMW K100 Custom by Z17 Customs-The BMW K100, otherwise known as the Flying Brick, certainly isn’t regarded as the prettiest bike created by BMW Motorrad’s engineers. The nickname derives from the blocky, 987cc inline four. However, the crew from Moscow’s […]
BMW K100 “Jetfighter” by Expressmoto Design-John Camara of Austin’s Expressmoto Design has an ideal pedigree for a custom bike builder. He’s been riding and racing both on- and off-road bikes for nearly four decades, reaching the upper classes of the […]
BMW K100 Cafe Racer by Z17 Customs-Today, we’re excited to feature this stunning 1988 BMW K100 cafe racer by Z17 Customs of Moscow. The design is by Mikhail Kostylev, executed by his partner Sergey Moonshn. As you may know, the K100 […]
Exclusive: BMW K100 Cafe Racer, “Optimus”-We’re proud to present this BikeBound exclusive: “Optimus,” a 1985 BMW K100RS cafe racer built by our new friend Stig Frydenberg from Norway. We actually solicited Stig to feature this bike, as it struck us […]