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Killer K: Mike Flores’ BMW K100 Cafe Racer

Killer K: A custom BMW K100 cafe racer by Mike Flores
Is this the year of the BMW K100? We reckon so. The earlier R-series boxers have held the limelight for long enough—and let’s face it, any R donor you find now either comes at a premium, or has already been hacked.

So if you’re looking for a classic Beemer, choose a K. You’ll get a unique, reliable engine—and some of the most awkward looks to come out of the 80s. Perfect for customization!

Killer K: A custom BMW K100 cafe racer by Mike Flores
LA-based Mike Flores is a fan. “I picked the K100 because I loved the design of the engine, the squareness and the sharp angles,” he says. “I wanted to make it into a bike that still honored the aspects of the original design that I liked the most.”

This very special K cafe racer is Mike’s first build (he’s actually a cinematographer by trade). The goal: trim the fat, and sprinkle on some modern upgrades.

Killer K: A custom BMW K100 cafe racer by Mike Flores
It sounds simple enough, but—as anyone who’s built a custom will attest—Mike had his work cut out. Even finding a suitable donor proved to be a mission.

“The bike I initially picked up was someone else’s half-assed project bike. I thought I’d be able to resurrect it,” he tells us. “It had a few nice components on it, but it was a deathtrap in the truest sense, and literally had a couple hundred thousand miles on it.”

Killer K: A custom BMW K100 cafe racer by Mike Flores
“But it did have a clean title: 1990 model year. So I set out to find a new donor bike, and found a really low mile 1987 K100 that was missing all paperwork. All that remains of the 1990 is the front half of the original frame, and the title.”

Mike has not only spliced together two different Ks, but also cherry-picked parts from several other bikes. Like the Suzuki GSX-R1000 upside-down forks, mounted via a steering stem and triples from Cognito Moto.

Killer K: A custom BMW K100 cafe racer by Mike Flores
“I got a lot of great advice and assistance over the phone from Devin Henriques at Cognito,” says Mike. “I think I’m the first ‘K’ guy to use his parts for a front end conversion.”

It doesn’t end there: Even though the wheels look like a matching pair, they’re actually from two different bikes. The front is a Triumph Sprint ST item, and the rear’s from a K1200RS. Mike got the front wheel hub machined down to space the brake rotors properly.

Killer K: A custom BMW K100 cafe racer by Mike Flores
Up front, the GSXR’s Brembo calipers are matched up to Triumph Speed Triple rotors. Both master cylinders are Brembo too; the front one was liberated from a Ducati Hypermotard, along with its throttle tube.

Mike turned to Rizoma for the reservoirs—and the brake and clutch levers—and then connected everything with custom lines from Galfer. He borrowed the switches from a Kawasaki Ninja (left) and a Ducati 999 (right), and added a carbon fiber front fender from a Ducati Monster 1200R.

Killer K: A custom BMW K100 cafe racer by Mike Flores
Mike built a new rear frame section, then started designing a tail piece. “I need to give credit to Cliff Meyer for building the rear cowl out of aluminum,” he says. “I sent him a cardboard template, but my aluminum welding and sheet metal skills weren’t up to par at the time.”

The new back end is suspended by a custom-made shock from Fox, and capped with a locally made seat. Mike tells us he tackled most of his fabrication work at Lucky Wheels Garage—a DIY workshop in downtown LA.

Killer K: A custom BMW K100 cafe racer by Mike Flores
BMW K100s are known for being reliable, so Mike just treated the engine to new rubber bits and consumables. He’s left the airbox intact too, but ditched the stock exhaust for a great looking four-into-one setup.

Who actually built this system, though, is anybody’s guess. “I found it on another K bike that I bought for some parts,” says Mike, “and then re-worked it by cutting it down behind the collector, and adding a Cone Engineering muffler from Lossa. Then I had it ceramic coated.”

Killer K: A custom BMW K100 cafe racer by Mike Flores
We asked Mike what the hardest part of the build was: “The wiring. The K100 has an ECU and an electronic fuel injection controller. There are also some critical circuits built into the stock instrument cluster, so installing an aftermarket gauge is anything but straightforward.”

“The solution involves a lot of DIY re-wiring, but I took my time with it—and relied on the help of the BMW internet forums. It all came together nicely.”

Killer K: A custom BMW K100 cafe racer by Mike Flores
So now there’s a whole new wiring harness—complete with AMP Superseal connectors. Mike’s also installed a new speedo, bar end turn signals, a bar end mirror and a keyless ignition, all from Motogadget.

There’s an LED headlight from Rigid Industries, and an LED tail light strip from Cognito Moto, integrated into the frame. Finishing kit includes Motodemic headlight brackets, rearsets from BSK Speedworks and a grippy set of Pirelli Diablo Angel GT tires.

Killer K: A custom BMW K100 cafe racer by Mike Flores
Mike sent the engine casings, frame and wheels off for powder coating, but he’s left the tank and tail as brushed aluminum. It’s a simple approach that suits the muscular, mechanical look of the K100 powerplant.

Ten months after starting the build, Mike now has a daily rider. “I’ve already put about 3,000 miles on it,” he says.

If this is the beginning of the K-series uprising, we’re in. Are you?

Mike Flores | Instagram | Images by Mike Flores

Killer K: A custom BMW K100 cafe racer by Mike Flores