In 1974, the company took a bold step by introducing the 898cc BMW R90S. With its gracefully curving bikini fairing framing a huge, jewel-like 8in headlight, the R90S looked like a bullet, an intercontinental road-seeking missile aimed at mountain passes from the Alps to the Rockies and everywhere in between. Its sheer audacity forever blew away the image of mom and pop tootling along on their "toaster-tank" /5 with Craven panniers. Here was a rare combination of luxury and true performance. Sporting riders drooled at the dual front disc brakes, that sexy fairing, narrow handlebar and the pair of Dell’Orto carburetors. Top speed was 125mph, with quarter-mile figures of 13.07 seconds @ 102mph reported by Cycle magazine. This was also the debut of the gorgeous 6.34gal fuel tank with knee cutouts. The silver/smoke S was followed in 1975 by the stunning Daytona Orange version, which sported drilled front disc brakes. 

Rumor, speculation and fabrication converged in 1976 as the motorcycling public became increasingly aware that BMW was planning something even bigger. Riders wondered how much displacement the new bikes would offer, and if the company could possibly top the R90S. 

The R100 lineup was first shown to the public at the Cologne motorcycle show in Germany in September of 1976. The engine had been bumped up to 980cc and made more powerful, the frame had been strengthened, the suspension improved, it was geared higher and the brakes had been upgraded. That graceful fuel tank from the R90S had been made standard across the line, and the ovoid valve covers had been replaced by rectangular units. But all eyes were on the new BMW R100RS, and the reaction was immediate. Riders and the press were stunned. Cycle magazine, in its December 1976 issue, said, "It’s so far from being staid that it makes [porn star] Harry Reems seem like Harry Reasoner." 

A telegram edged in black
Years ago, I interviewed Hans Muth, the leader of the BMW R100RS design team and the first motorcycle stylist to work for BMW. After working on the /6 and R90S, he was instructed to design a new model; a comprehensive, innovative, emotional, functional motorcycle with a major emphasis on aesthetics. He was not influenced by existing fairings, which he called "added on, strange looking, ugly, massive and boring. They looked weird with their rough shells surrounded by a flexible black molding — like a consolation letter stating somebody’s death." 

The RS fairing was essentially done in one take from a reference model. Only slight detail changes were made afterwards, such as enlarging the down-force wings below the headlight. A wind tunnel was utilized to design the fairing, and in 1980 the German magazine Motorrad rented the Volkswagen wind tunnel to test it. Keeping in mind that the coefficient of drag (Cd) for a flat surface moving through the air is 1.0, the article pointed out that the Cd for an unfaired R100 was 0.627, the R100S was 0.589, and the RS’s a slippery 0.571.