Valtoron Used Sand Casting Techniques to Sculpt This Unique BMW R100RS

During the ‘70s, BMW Motorrad’s vicious R100RS enjoyed a fair deal of attention from the press and moto enthusiasts alike. To be fair, that’s no wonder. Not only was this piece of machinery ahead of its time in terms of performance, it also featured an innovative design that brought about an unrivaled level of comfort.

Take, for instance, a 1977 model in BMW’s revered range. This humungous tourer is put in motion by a menacing four-stroke horizontally opposed boxer-twin engine that hosts two Bing carburetors and a total of four valves. The air-cooled OHV monstrosity prides itself with a compression ratio of 9.5:1 and a colossal displacement of no less than 980cc.

This untamed beast is perfectly capable of delivering as much as 70 hp at around 7,000 rpm, while a crushing torque output of 56 pound-feet (76 Nm) will be achieved at approximately 6,000 rpm. A five-speed gearbox channels the powerplant’s unholy force to the rear 18-inch multi-spoked wheel by means of a shaft final drive.

As a result, R100RS is blessed with a top speed of 120 mph (193 kph) and a respectable 0-62 mph (0-100 kph) acceleration time of just 4.6 seconds. On the other hand, stopping power is taken good care of by twin 260 mm (10.24 inches) brake rotors and two-piston calipers that sit on the front 19-inch wheel, coupled with a 200 mm (7.9 inches) simplex drum setup at the rear.

The powertrain is hugged tightly by a steel double cradle frame, which rests on a set of cartridge fork at the front. On the opposite end suspension duties are handled by dual shock absorbers and a double-sided swingarm. This whole ordeal permits up to 7.9 inches (200 mm) of travel up front, along with 4.9 inches (125 mm) of rear wheel travel.

All things considered, this machine is a genuine showstopper, even by today’s standards. As such, we’d imagine the Spanish surgeons over at Valtoron were delighted to have been tasked with working their magic on a ‘77 R100RS!

Look, these folks aren’t your regular Joes when it comes to custom works of two-wheeled art. Instead of adopting the latest metal shaping techniques and state-of-the-art tools, the Madrid-based firm crafts its astonishing one-off bodywork modules by means of sand casting.

As soon as the ride was stripped bare of any stock panels and its boxer-twin behemoth was sent off to be rebuilt by Max Boxer’s engine specialists, the Valtoron duo tackled the painstaking process of fabricating an array of cast aluminum parts that were to replace R100RS’ stock units.

These include a gorgeous fairing that houses the bike’s headlight and new fenders equipped on both ends. Additionally, the fresh fuel tank and tail section form a single monocoque structure that does a sweet job at looking the business.

To accommodate this classy goodness, Valtoron went about building an otherworldly exhaust muffler and one neat subframe from scratch. The latter is gripped by a pair of Hagon shocks that’ll provide a considerable improvement in the handling department. Furthermore, the front suspension was also treated to an extensive overhaul.

Finally, the finishing touches consisted of installing a selection of aftermarket components, such as rear-mounted foot pegs from Raask and top-grade Continental tires, as well as clip-on handlebars that wear Magura grips. Last but not least, this magnificent entity was codenamed Rhombus 1000.

What’re your thoughts on Valtoron’s surreal undertaking?