Blue Moon: BMW K100 Café Racer by RW Motorcycles

BMW K100 Cafe Racer

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 to assume that the BMW designers behind the company first four-cylinder motorcycle would be surprised to see these aging ‘Bricks transformed into such beautiful creations.

BMW K100 Cafe Racer

Once such customizer is Francisco of Rusty Wrench Motorcycles, located on Portugal’s Algarve Coast. After building his first bike in 2015, Francisco has expanded his business so that he’s building full-time, as well as managing a store open to the public — a dream come true. Last year, their Suzuki GSX1200 Inazuma was selected as one of Bike magazine‘s Custom Bikes of the Year, and we recently had the honor of featuring their “Poseidon” GPz1100.

BMW K100 Cafe Racer

Now Francisco is back with “Blue Moon,” a 1986 BMW K100RT built for client who wanted a modern cafe racer. Given the vast array of custom work and updates, it’s hard to imagine that this bike rolled out of the factory some 33 years ago!

Below, we get the full story on this futuristic Flying Brick.

K100 Modern Café: Builder Interview

BMW K100 Cafe Racer

• Please tell us a bit about yourself, your history with motorcycles, and your workshop.

My name is Francisco and motorcycles were always a big passion in my life. I built my first bike in 2015, which was a great success. After that I did some kustom building for friends, but now I am finally doing it full-time for my clients! You can see other projects done in our website.

I created the brand Rusty Wrench Motorcycles with an open store to the public in 2017, with some accessories and clothes for biker lovers in Faro, Portugal. This was an old dream of mine that came true!

BMW K100 Cafe Racer

• What’s the make, model, and year of the bike?

BMW K100 RT of 1986.

BMW K100 Cafe Racer

• Why was this bike built?

It was a customer project.

BMW K100 Cafe Racer

• What was the design concept and what influenced the build?

It was inspired in a futuristic concept.

BMW K100 Cafe Racer

• What custom work was done to the bike?

* Handmade Sub frame and rear end

* Handmade Rear tailight made of polycarbonate

* Handmade Headlight fairing

* Handmade Seat

* Handmade Plate number frame

* Handmade Front fender

* Handmade footpegs

It was also customized with:

* Stainless steel exhaust

* Inverted front suspension

* YSS rear suspension

* Gas tank cap

* Stainless steel air intake system with K&N air filter

* Moto Gadget speedometer,

* Moto Gadget M-lock digital ignition

* Moto Gadget grips

* Moto Gadget turn signals

* Metzeler tires

BMW K100 Cafe Racer

• Does the bike have a nickname?

“Blue Moon.”

BMW K100 Cafe Racer

• How would you classify this bike?

Café modern

BMW K100 Cafe Racer

• Was there anything done during this build that you are particularly proud of?

The custom parts are all handmade and it was really rewarding to see the final result.

BMW K100 Cafe Racer

Follow the Builder / Photographer

RW Motorcycles
Instagram: @rwmotorcycles
Facebook: rwmotorcycles2015

Photographer credit:
Bruno Félix
Instagram: @bfelix_1979
Facebook: @Bfelixphotos


  1. Can’t be a Rusty Wrench…if that wrench is building bikes like this! Neat scoot!!! Love the paint!

  2. Nicest K series I’ve seen

  3. Richard Mumaw

    What would be the cost to convert my 1985 K100rs to the Beautiful Bike you have?

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