Los Angeles, California-based custom shop Roughchild Motorcycles has specialized in air-cooled BMWs since 2012. Focusing on the Bavarian brand, founder Robert Sabel has seen innumerable trends come and go over the years. So, instead of jumping on the next fad, Roughchild maintains a classic and understated aesthetic. Despite the old-school approach, the custom garage doesn’t skimp on performance either. Its Ruby R75 RSWB is a prime example.

Based on the 1973 BMW R75/5, Roughchild's Reisesport Short Wheel Base (RSWB) project combines show with modern go. Roughchild starts each build by repairing the aging frame and adding a custom subframe complete with integrated taillight and indicators. A pair of Ohlins rear shocks bridge the gap between the original swingarm and new subframe. Of course, the reservoir units aren’t exactly period-correct, but they certainly improve the old Beemer’s ride quality.

Gallery: Ruby R75 RSWB: 1973 BMW R75/5

The front end receives similar accommodations with a Showa USD fork sharpening the café racer’s handling. Dual Brembo calipers and twin wave rotors bulk up the R75’s stopping power, but a drum brake unit remains at the rear. Sabel laces the stock rear hub and custom front hub to a set of Excel rims. Bridgestone Spitfire tires also deliver more enough performance for the road.

At 749cc, the R75’s produced 50 horsepower, a respectable number for its day. However, Sabel’s chassis refinements prompted a serious engine overhaul. Bored out to 1,000cc, the air-cooled opposed-twin also received tuned Mikuni carburetors and a modified airbox. Lastly, a stainless-steel exhaust opens the RSWB’s airways, resulting in 60 horsepower and 52 lb-ft of torque.

Along with the mechanical revisions, Roughchild also installed a hi-torque starter, lightweight lithium battery, and replaced the factory charge system. A Motometer Speedometer seamlessly integrates into the vintage headlight housing and new switchgear simplifies the Beemer’s controls.

With all the pieces in place, the RSWB earned a Granada Red paint job with chrome accents and ceramic roundels. This is the first Ruby R75 to roll out of Roughchild’s Los Angeles garage, but the shop will build 9 more for customers before ending the custom campaign.

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