Prior to the release of the R90S at the end of 1973, BMW motorcycles were considered stodgy, conservative, and plainly unexciting. A BMW was great for hauling sidecars or long distance cross country trips, but it was hardly a sports bike. If you were younger than forty it simply wasn’t cool to be seen on one. But the R90S changed that.
In its day the R90S provided unsurpassed on the road performance, but even more significant than the performance was its style. Styled by the legendary Hans A Muth, the R90S was the first production motorcycle to feature a factory-fitted fairing as standard equipment.
And if the café-racer look wasn’t enough to make the R90S stand out from the crowd the paint scheme was. Early examples came in smoke black, and from 1975 Daytona Orange was an option. With hand-painted pin striping and a horrendous price tag, in the mid-seventies there was just nothing else like the R90S. This was the machine that epitomised the era. An emphasis on style was in ascendance, and the R90S was marketed as a luxury accessory for the new breed of affluent motorcyclist.
The R90S engine was based on the R90/6 touring model. Also released at the end of 1973, this was a development of the R75/5 that appeared in 1969. Updates included a five-speed gearbox and larger alternator for more reliable starting.
Whereas the oversquare 90×70.6mm dimensions were shared between the 90/6 and 90S, the R90S had higher compression pistons and larger carburettors to crank out its 67 horsepower. Rather than the ubiquitous Bing carburettors as fitted to every BMW motorcycle in living memory, Italian 38mm Dell’Orto pumpers graced the R90S. And while the Italians continued to fit noisy, antisocial, mufflers the R90S remained whisper quiet, right up to the top speed of around 200 km/h.
It was also easy to live with, and most maintenance tasks were well within the capability of the owner. Easily adjusted pushrods operated the valves and the tried-and-true points ignition was conveniently located at the front of the engine.
Even if the floating single piston ATE brake calipers lacked ultimate power, the twin 260mm front disc brakes also set the R90S apart. With its shaft drive and long travel suspension the R90S also lacked the sharpness and handling precision of comparable Italian sportsters but more than made up for it in civility.
Practical features previously unheard of on motorcycles abounded. Instrumentation inside the beautifully finished fairing included a clock and ammeter. The front brake master cylinder was located out of sight, under the fuel tank, as was a three-way adjustable hydraulic steering damper. When it came to the toolkit the R90S left every other motorcycle in the shade. Not only comprehensive, this included an official BMW towel, tyre repair patches, and a tyre pump under the seat.
But the R90S was not style without substance. On the road it excelled. The frame, with its bolted on rear subframe may have been found wanting in terms of ultimate strength but for most purposes it was more than adequate. Long travel suspension provided a plush ride but was also sufficiently damped for spirited riding.
A 24-litre fuel tank provided a touring range close to 400 kilometres and the comfort level was unmatched. BMW’s first, and arguably its best ever Superbike, the R90S did everything and was even a successful Superbike racer. Helmut Dähne and Hans Otto Butenuth rode an R90S to victory in the 10-lap Isle of Man production TT in 1976. Dähne’s best lap of 164.95 km/h is still the best ever at the Isle of Man by a pushrod boxer twin. The most impressive R90S racers were those of the US importer Butler & Smith prepared for 1976 by BMW guru Udo Gietl.
These had special monoshock frames, shortened cylinders for additional ground clearance, and produced around 100 horsepower. After Steve McLaughlin won the first ever Superbike race at Daytona in 1976, Pridmore went on the give BMW the AMA Superbike title. This was to be their only major series racing victory.
Over a short three years BMW sold as many R90Ss as they could make, 17,455 before the R100S replaced it in 1977. The R100S eventually became the R100CS but it is the R90S that stands out and is remembered. The R90S is unquestionably the classic BMW motorcycle of the modern era.
Australia’s go-to-guy for classic motorcycle wisdom. Ian has written nearly 45 books on motorcycles that each offer unparalleled insight on the historical and technical development of particular makes and models.