Dark Pearl: BMW K100LT by Rusty Pipes Garage

“Imagine riding a wild animal dressed up in a tuxedo…”  

The BMW K series remains an interesting piece of motorcycling history and technology. In the late 1970s, BMW Motorrad was worried about their iconic Airhead machines falling too far behind the times, making them a niche player in the global motorcycle market — much like Moto Guzzi and their pushrod V-twins. They decided a radical change was needed.

Engineer Josef Fritzenweger led a small team to develop a prototype with a four-cylinder laid on its side in the frame, utilizing a Peugot 104 (automobile!) engine. After gaining proof of concept, they destroyed the prototype and set out to create an inline four-cylinder motorcycle engine, borrowing technology from the company’s automobiles, including Bosch Jetronic electronic fuel injection.

The production version made 90 horsepower, and the K100 was unlike any BMW motorcycle ever seen, quickly gaining a reputation as the “Flying Brick.” It could do 0-60 in 4.1 seconds, hit 133 mph at full song, and a barrage of new patents meant the Japanese manufacturers wouldn’t be able to copy the new machine. Later the BMW K100LT (Luxury Touring) came along, a fully-faired tourer more reminiscent of a Goldwing than a high-speed cruise missile.

Our friend Leonidas of Greece’s Rusty Pipes Garage began customizing bikes at the tender age of 14, overhauling his father’s ’78 Suzuki A50. After his military service, he studied mechatronics — a multidisciplinary branch of engineering that focuses on both electrical and mechanical systems — and began building custom bikes professionally.

This customer project began as a K100LT, though it’s been stripped down, transformed, and highly tuned. It’s now running a Suzuki GSX-R front end, Ducati rear suspension, and a custom subframe that holds the ECU, lithium battery, and a liquor flask for the coolant overflow. Leonidas fabricated new side covers, lots of brackets, and a stainless 4-in-1-in-2 exhaust system with handmade mufflers.

When everything was painted, powdered, and put back together, he turned over the engine tuning to Bike Therapy, who made sure the bike was performing at a higher level than ever before. Says Leonidas of the riding experience:

“If you can imagine riding a wild animal dressed up in a tuxedo…”

He says the entire build, nicknamed “Pearl,” represents what the Greek call “meraki” — a word for which we don’t have an equivalent in English:

“This is a word that modern Greeks often use to describe doing something with soul, creativity, or love — when you put ‘something of yourself’ into what you’re doing, whatever it may be.” —NPR

No doubt, Leonidas has transformed this Flying Brick into a pearl. Below, we talk to him for the full details on the build.

BMW K100LT Custom: Builder Interview

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

The donor bike is a 1985 BMW K100LT.

• Why was this bike built?

It was a customer’s project.

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

Having seen many projects online, I combined them and added my own variations for a unique result.

• What custom work was done to the bike?

I started by cutting the subframe and building a new one with a grid in which I have placed the ECU and a lithium battery. The radiator reserve tank is replaced with a liquor flask underneath the new subframe.

Then, I replaced the factory front end system with a new one from Suzuki GSX-R K8 to which I adapted the factory rim with new Dunlop Trailmax Mission tires with adapters in order to fit the new racing Galfer brake discs. In addition, I also built brackets for the front fender on it!

I adapted fat-bar risers with a new handlebar and turn signals. After that I made a new dash panel where I located indicators and switches. Next to it I installed a Velona Speedometer!

The taillight and headlight are also aftermarket, so I adapted the appropriate bases. Specifically, the taillight was placed on a custom bracket which also holds the rear fender and the license plate.

I used the factory gas tank with a new cap and fabricated side metal covers. The construction of the rear shock absorber lever was made in the garage after using a CNC laser to cut the plates! The suspension donor is a Ducati.

Additionally I used the factory stainless exhaust pipes and fabricated a 4-in-1-in-2 adapter for the handmade mufflers. After that the pre-filter box was replaced with a new stainless handmade one with aftermarket air filters.

The metal base for the saddle is covered with alcantara and leather by ST Covers and HD Electronics took over the electrical stuff.

Finally, most parts of the motorcycle were powder-coated by Troxonet. The engine, the differential, and the tank were painted in the garage.

After putting them together, Bike Therapy took over the engine tuning, which brought the motorcycle’s power to a complete new level.

• Does the bike have a nickname?

Pearl.

• Can you tell us what it’s like to ride this bike?

If you can imagine riding a wild animal dressed up in a tuxedo…

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

Nothing particularly! Every single job on this motorcycle represents the Greek word “Meraki,” which means passion for what you do!

Build Progress Shots

Builder Thanks

Saddle Fabricator: www.facebook.com/stcovers
HD Electronics: www.facebook.com/HD-electronic-services
Bike Therapy: www.facebook.com/BikeTherapyPatras.official
Powder Coating: troxonet.com

Follow the Builder

Garage IG: @rusty.pipes.garage
Fabricator IG: @leonidas.rusty