In the world of custom motorcycles, the finest builds do far more than restore aging machines—they reinterpret them for a new generation of riders. Roughchild’s Waud Commission, exemplifies this philosophy. Starting with a neglected 1974 BMW R90/6 that was destined for the scrapyard, the workshop transformed the classic airhead into a meticulously engineered café racer that seamlessly combines vintage BMW heritage with modern performance, handcrafted craftsmanship, and personalized design.
The donor motorcycle was anything but a promising foundation. Acquired after an unexpected cold email offering a “broken motorcycle,” the R90/6 was purchased for just $1,500 without ever being started. Upon arrival, the bike was immediately stripped to its bare frame, revealing a machine in desperate need of a complete mechanical and cosmetic restoration.
Rather than performing a period-correct restoration, Roughchild used the opportunity to create a thoroughly modern interpretation of BMW’s iconic boxer twin while carefully preserving the soul of the original motorcycle.
A Carefully Engineered Performance Upgrade
Although the motorcycle began life as a factory 900cc BMW R90/6, the engine now follows Roughchild’s proven formula. The original air-cooled boxer has been enlarged to 1,000cc using BMW’s own engineering philosophy as the foundation.
Because BMW utilized essentially the same bottom-end architecture across several members of its classic R-Series lineup—including the R75 and R100—the workshop confidently upgraded the top end to 1,000cc while maintaining factory reliability. Rather than chasing excessive displacement, Roughchild deliberately stayed within the limits BMW originally engineered, avoiding the compromises associated with extreme big-bore conversions.
Performance improvements extend well beyond displacement.
One of the most significant upgrades is the replacement of the original Bing constant-vacuum carburetors with a set of modern Mikuni carburetors, widely regarded among BMW airhead enthusiasts as one of the most worthwhile modifications available. The Mikunis deliver noticeably sharper throttle response, improved power delivery, leaner fuel consumption, simplified tuning, and greater long-term reliability compared to aging factory carburetors that inevitably suffer wear after decades of service.
The original airbox remains in place but has been modified with drilled openings inspired by the legendary BMW R90S, subtly improving airflow while preserving the motorcycle’s classic appearance.
Modern Chassis with Classic DNA
While much of the motorcycle still carries its original BMW identity—including the frame, engine case, and portions of the drivetrain—Roughchild introduced carefully selected upgrades from across BMW’s extensive R-Series lineage.
The rear features a shorter /5 swingarm and driveshaft assembly, subtly altering the bike’s proportions while sharpening its handling characteristics. Suspension duties are handled by premium Öhlins Blackline shocks that provide external adjustment for both damping and preload, allowing riders to tailor ride quality for everything from spirited canyon roads to relaxed touring.
At the front, the transformation is even more dramatic.
Instead of restoring the original forks, Roughchild engineered a completely custom front end based on the modern BMW R nineT. New forks, brake rotors, calipers, hub, and front fender dramatically improve braking performance and chassis precision while maintaining harmonious styling. Brand-new Excel rims, fresh spokes, upgraded brakes, stainless brake lines, and handcrafted components complete the comprehensive suspension overhaul.
Bespoke Styling Inspired by Porsche Heritage
Visually, the Waud Commission strikes a careful balance between understated elegance and aggressive café racer aesthetics.
The motorcycle wears Porsche Fashion Grey, a timeless color first introduced on the Porsche 356 during the 1950s. The muted finish complements numerous black accents, including Cerakoted exhaust headers, reverse-cone stainless mufflers, suspension components, and other carefully selected trim pieces, giving the bike what Roughchild describes as a “semi-murdered-out” appearance without sacrificing sophistication.
Customer preferences played a significant role throughout the project. An R100 fuel tank was selected to achieve a specific visual profile inspired by one of Roughchild’s previous builds, while a completely custom seat and rear subframe were fabricated from scratch. The taillight has been seamlessly frenched into the frame, creating a clean rear profile that avoids unnecessary visual clutter.
Even seemingly minor details received careful attention, including period-correct colored hand controls requested by the client, custom BMW-inspired cable ties, vintage-inspired badging finished in black and gold, and an authentic BMW horn sourced from an R80 GS simply because it retained the unmistakable sound characteristic of classic BMW motorcycles.
Modern Electronics Without Compromising the Design
One of the defining characteristics of the build is how modern technology has been discreetly integrated into the vintage platform.
The bulky factory instrument cluster was discarded in favor of a custom-machined top triple clamp housing a compact Motogadget digital speedometer. Additional controls are neatly concealed within the headlight housing, while Motogadget m-Blaze bar-end indicators provide contemporary lighting without disrupting the motorcycle’s minimalist silhouette.
The handlebars also blend components from multiple BMW generations, combining later-model switchgear with classic styling and Renthal grips specifically chosen to accommodate integrated turn signals. Meanwhile, the brake master cylinder has been relocated beneath the fuel tank, preserving the clean cockpit appearance.
Preserving Heritage Through Thoughtful Innovation
Perhaps the most remarkable aspect of Roughchild’s Waud Commission is its restraint. Rather than radically reinventing the BMW R90/6, every modification serves a clear engineering or aesthetic purpose. Original BMW components remain wherever appropriate, complemented by carefully selected aftermarket upgrades and custom-fabricated parts that elevate both performance and refinement.
The finished motorcycle is not merely a restored 1974 BMW—it is a carefully curated evolution of the classic airhead platform. By blending period authenticity with modern engineering, premium components, and bespoke craftsmanship, Roughchild has created a café racer that feels equally at home honoring BMW’s rich heritage and carving modern back roads.
As the owner prepares to fly in and collect the finished machine, the Waud Commission stands as another testament to how thoughtful customization can breathe new life into a forgotten classic while respecting the engineering legacy that made it iconic.
Source: Roughchild
