Sport-Evolution: BMW R100GS Enduro

Sport-Evolution builds a lighter, more powerful GS…  

In 1987, BMW unveiled the new evolution of their groundbreaking R80G/S. The original G/S (“Gelande/Strasse,” or Terrain/Street) hadn’t just proven itself in the Paris-Dakar Rally, but helped to define the Adventure Bike class:

“In the late Seventies, conventional wisdom said that any motorcycle with off-road aspirations was small, light and had one cylinder: But just 25 years ago, BMW ‘escaped’ this idea and launched a bike, the R80G/S, that created a whole new category — the large adventure/touring sportbike.” –Motorcycle Classics

In comparison to the original G/S, the new R100GS offered more displacement (980cc) along with BMW’s Paralever rear suspension, which added a torque rod to prevent “jacking” under hard acceleration — a criticism of the original R80G/S. The R100GS also boasted beefier 40mm forks, a 17-inch rear wheel, new bodywork, and spoke wheels that could run tubeless.

While the new GS was bigger and heavier than its predecessor, it was still a lightweight compared to the adventure bikes of today. At 550 lbs dry, a modern R1250GS weighs nearly 100 pounds more than a 455-lb R100GS. Sure, power has risen with weight, but anyone with an ounce of dirt-riding experience knows that more power doesn’t make up for added bulk — there’s a sweet spot between ponies and poundage. Many would argue the GS models of the 1980s nailed this balance better than today’s adventure bikes.

Enter Germany’s Sport-Evolution, a premier BMW customization workshop and parts supplier founded and led by Dietmar Franzen. The company specializes in modernizing and transforming two-valve BMW models into fully TÜV-legal cafe racers, bobbers, scramblers, and enduros.

“Each bike is tailored to the individual customer’s wishes through our own online configurator (konfigurator.sport-evolution.de) and beyond. As a result, every custom bike is a unique masterpiece, built exclusively upon request.”

The bike you see here is the company’s R100GS Enduro model, which harks back to the early days of the Gelande/Strasse machines.

“The design concept is clearly inspired by the classic enduro motorcycles of 1980s off-road sport… Our goal was to bring that origin back to life. When you look at early KTM GS models or the first BMW G/S models, they were lightweight, minimalistic, and very pure motorcycles. That exact feeling is what we wanted to recreate.” -Dietmar Franzen

Sport-Evolution builds this model to a variety of specifications. In the case of the 1990 R100GS you see here, the engine was rebuilt to 1070cc with a dual ignition for an output of ~85 hp and 90 Nm (66 ft-lbs) of torque, offering about 25 hp more than the stocker. Dietmar says they offer from near-stock performance to a stout 100 hp / 100 Nm.

The suspension was upgraded with high-quality components, vintage enduro bodywork was added, and a narrower tank gives the rider better freedom of movement while still offering 21 liters (5.5 gallons) of fuel capacity.

Without luggage, the dry weight is approximately 170 kg (375 lbs) — about 80 pounds lighter than a stock R100GS! Combine that with the 40% power upgrade and better suspension, and it’s a whole new bike.

“This results in an extremely light and agile machine with strong performance in both chassis and engine… Compared to modern motorcycles with similar power, which often weigh around 300 kg and use very long gearing, much of the liveliness is lost. This motorcycle, by contrast, is geared relatively short, comparable to a Golf GTI. Even though the engine produces ‘only’ about 85 hp on paper, the bike feels very direct and dynamic.”

As you can see in the video, the bike looks like a hoot on the trails. We’re happy that shops like Sport-Evolution are breathing new life into these aging two-valve boxers, bringing back the days when purity of design defined the world of adventure riding. 

Below is our full interview with Sport-Evolution, featuring founder Dietmar Franzen. 

BMW R100GS Restomod Enduro: Builder Interview

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

Sport-Evolution Franzen GmbH, based in Neuwied, is one of Europe’s premier addresses for high-end BMW motorcycle customizing. Led by Dietmar Franzen, the company combines decades of professional racing experience with cutting-edge manufacturing technologies, such as CAD design and 3D printing.

The manufacturer’s primary focus is the creation of their signature “SE Concept Bikes.” These projects involve the elaborate, handcrafted disassembly of classic BMW 2-valve models, which are then technically modernized and transformed into charismatic Cafe Racers, Bobbers, or Scramblers. Every bike is designed as a “new vehicle build,” meaning the engine, chassis, and electronics meet the highest quality standards. They are delivered “Ready to Ride” with full TÜV certification.

Beyond vehicle construction, Sport-Evolution operates an extensive online shop for conversion parts and offers specialized workshop services ranging from engine overhauls to a world-exclusive ABS retrofit for classic bikes. Through a perfect symbiosis of classic design and modern reliability, Sport-Evolution turns the dreams of discerning motorcyclists into reality.

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

This enduro is based on a 1990 BMW R100GS, but we offer this concept for all 2-V GS models.

• Why was this bike built? 

Sport-Evolution offers a wide variety of different models, including Bobbers, Scramblers, Roadsters, Cafe Racers, and Enduros. Each bike is tailored to the individual customer’s wishes through our own online configurator (konfigurator.sport-evolution.de) and beyond. As a result, every custom bike is a unique masterpiece, built exclusively upon request.

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

Dietmar Franzen: The design concept is clearly inspired by the classic enduro motorcycles of 1980s off-road sport. We deliberately wanted to move away from the modern interpretation of an enduro, which today is often perceived more as a travel motorcycle. Modern enduros are tall and feature a high-mounted front fender, but they often share very little with the original spirit of enduro riding.

Our goal was to bring that origin back to life. When you look at early KTM GS models or the first BMW G/S models, they were lightweight, minimalistic, and very pure motorcycles. That exact feeling is what we wanted to recreate.

• What custom work was done to the bike?

Dietmar Franzen: The selection of components is consistently based on classic off-road sport. This applies in particular to the front and rear fenders, as well as many other details. Some components come from Acerbis, a manufacturer specialized exclusively in enduro products.

A narrower fuel tank was installed to significantly improve freedom of movement. Overall, the motorcycle has been systematically reduced in weight across many areas in order to technically realize the original, sport-oriented concept.

• Any idea of horsepower, weight, and/or performance numbers?

Dietmar Franzen: We offer various performance levels. The motorcycle shown here features a completely rebuilt 1070 cc engine with dual ignition. Output is approximately 85 hp and around 90 Nm of torque.

In general, we offer everything from near-stock performance up to 100 hp and 100 Nm. The weight depends heavily on the specific configuration, for example whether luggage is mounted or which exhaust system is installed.

In the configuration shown here, without luggage, the dry weight is approximately 170 kg. In addition, there are 21 liters of fuel capacity.

We always state the weight without fuel. The reason is that a larger tank would otherwise mathematically increase the total weight and make the motorcycle appear disadvantaged in the technical specifications, even though the larger tank is functionally an advantage. 

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

Dietmar Franzen: The motorcycle feels significantly more agile and lighter. High-quality suspension components ensure precise handling. The knobby enduro tires emphasize the off-road character, but in their modern form they also deliver very good performance on the road. Overall, this results in an extremely light and agile machine with strong performance in both chassis and engine.

Compared to modern motorcycles with similar power, which often weigh around 300 kg and use very long gearing, much of the liveliness is lost. This motorcycle, by contrast, is geared relatively short, comparable to a Golf GTI. Even though the engine produces “only” about 85 hp on paper, the bike feels very direct and dynamic.

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

Dietmar Franzen: Above all, I am convinced by the overall appearance of the motorcycle. When I think of enduro sport from the 1980s and 1990s, this bike corresponds exactly to the image I have in mind.

Whether you would call that pride or not is another matter, but in terms of the selection and combination of components, it is a perfect result. The level of craftsmanship and the overall coherence of the motorcycle are exceptionally strong.

From day one, people have said, “I want this.” Even the motorcycle in the showroom was immediately requested by a customer. He explicitly said he did not want a newly built example, but this exact bike. I offered to build another identical one, but he insisted on having this very motorcycle. 

Video Review (in German)

Follow the Builder

Website: www.sport-evolution.de
YouTube: @Sport-Evolution_de
Instagram: @sportevolution.de
Facebook: @sportevolution.de

Photographers: Aaron Zimmermann / Dietmar Franzen