On pure performance. BMW's R90S was not the
fastest superbike of the mid-1970s. Nor was it the quickest around a
racetrack: at least, not often. But for a rider with a long distance to
travel on straight roads and twisty ones, there was nothing on two wheels
that would prove faster or more comfortable than the uniquely well-equipped
flat twin.
The BMW's distinctive smoked paint scheme was
perfectly in keeping with its image as a very refined and expensive
sports-tourer. In many respects, the R90S was the best all-round superbike
of its day. Certainly, no other production machine could match its
combination of I25mph (2()lkm/h) top speed, relaxed high-speed cruising
ability, fine handling, reliability and impeccable finish.
BMW had plenty of practice in building horizontally
opposed twins, and it showed. The R90S came from a line of fiat twins
stretching back to Max Fritz's original R32 of 1923. The German firm had
been building competent, comfortable and conservative tourers for many
years. But this bike, shaped by noted stylist Hans Muth. had a distinctly
more aggressive personality. The basics were typical BMW. Like the
naked R90/6. which was launched at the same time in 1973. the R90S owed much
to the previous year's R75. Enlarging the 745cc R75's bore from 82 to 90mm
while retaining the 70.6mm stroke increased capacity to 898cc. BMW also made
a few other updates, including a revised gearchange mechanism, more powerful
280W alternator and stronger bottom end. There was more to the S-bike
than just its fairing.
The engine was given a higher compression ratio.
9.5:1 against the 9:1 of the R90/6. and breathed in through big 38mm
Dell'Orto carbs with accelerator pumps. Maximum power was 67bhp at
7()00rpni. an increase of 7bhp over the standard model. The R90S also had a
steering damper in its cockpit, a larger fuel tank and a second front brake
disc. The extra power gave the S model a worthwhile boost at high
revs, without hindering either its torquey mid-range response or its
smoothness at most engine speeds. Better still, the fairing meant the
engine's performance could be fully exploited by the rider, who was free of
the wind-blast generated by every rival superbike. Other manufacturers would
soon follow BMW's lead, but for the moment the fairing put the R90S in a
class of its own.
Comfortable ride
Handling was good. too. despite suspension that was soft enough to give a
comfortable ride. Notwithstanding its steering damper the S sometimes felt
light at the from when approaching its lop speed, but That was even more
true of most naked rivals. The twin-disc from brake system was reliable but
lacked feel until uprated in 1975. Neat touches included a dashboard clock,
generous fuel range of 200 miles (322km) or more, and a seal that allowed
the rider lo cover that distance in comfort. BMWs had never been
cheap, and the R90S. with its all-inclusive specification, was no exception
to this rule. In many markets it was more than twice the price of Honda's
CB750. Thai ensured the R90S would be ridden only by a select band of
riders. Although the bike was a success, it was outsold by the standard
90/5. Those riders fortunate enough lo cover serious distance on the
R90S knew that it was a very special motorcycle. If what you needed was a
speed, handling ability and comfort, the R90S delivered in style. Oh. and
sometimes it was (he quickest superbike round a racetrack, too. BMW ace Reg
Pridmore's victory in the 1976 US Superbike championship was proof of that.
Ask a rider in the late
1960s what he thought of BMWs - girls virtually never rode motorcycles, so I can
use the pronoun "he" with some certainty - and the response would have been
along the lines that they were solid, reliable workhorses ridden by hard men who
thought that using a plastic bag to sleep on in a blizzard was a sign of effete,
limp-wristed decadence.
BMWs of the period came in a wide range of colors. There was black, black, black
and black. Customizing a BMW meant painting it white. White demonstrated a
confused sexual orientation and was therefore very suspect.
Because BMW riders tended to like their bacon sandwiches still attached to the
hind legs of a wild boar, which they could then bare-handedly fight to the
death, and felt that consuming 10 gallons of Weise beer before a ride was the
least any real man could do, BMWs were started manually courtesy of a tiny pedal
attached to the rear of the gearbox. Mainstream humans failed miserably at this
task, but the Uber Beings who rode BMWs could manage to fire up the Bavarian
Flat Twins using no more than the end of their little finger or, in an
emergency, perhaps the tip of their left ear lobe. In short, BMWs lacked
mass-market appeal. All this was about to change.
As the 1960s departed and the new, flower-tied, flared-jeaned and pink-shirted
1970s were born, BMW hit the biking world with a whole range of truly
outstanding motorcycles. And at the very top of this new, shiny tree was the
R90S.
The R90S was one of the cleverest motorcycles ever to be produced and was proof
positive that deep in southern Germany BMW's marketing team really understood
the problem they faced. In addressing the factory's image of staid, dull
reliability they managed to do that smartest of all three card tricks: retain
their existing customers, bring on new ones - and do so cost-effectively.
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Technically, the R90S was light years behind the
best of the Japanese and was nothing more than a modest technical step up from
earlier Boxer Twins. Thus, the shaftdrive was retained, as was the two-valve,
horizontally opposed, push-rod twin-cylinder engine. This was not
state-of-the-art engineering by any stretch of the imagination. But what an
engine the Germans produced! The new powerplant, with its five-speed gearbox,
still looked, sounded and felt like previous BMWs, but this was a motor which
had been to the gym for a serious work out.
The three aces the R90S had to play were usability, fitness for purpose and
utter, totally, unburstable reliability. With at top speed of less than 120 mph,
the R90S lost out to the true hyper sports bikes of the day and was, on paper,
no faster than Triumph's 750 Bonneville or the Honda CB750. The big difference
was that the BMW's 120-mph top speed equated to a solid 115-mph cruising
performance.
This point needs stressing. Riding an R90S, it was comfortably, practically and
realistically possible to cover 90 miles in an hour and 150 plus in two hours.
Nothing else in the bike world, and very few cars of the time, could offer this
supreme distance-devouring performance. Miles didn't disappear beneath the BMW's
wheels - whole countries simply zipped past in a satisfying blur.
Critics of the motor complained, justifiably, that the gearbox was dreadful
compared with the Kawasaki Z1 - which it was. BSA group Triple owners boasted
that their bikes offered vastly better handling - and this too was true. And the
supremely refined Honda CB750 was infinitely smoother. But when the BMW rider
looked at his map and saw that there was 1500 miles of hard riding ahead, there
was always going to be only one winner.
The chassis complemented the motor wonderfully. The R90S was never the hyper
sports bike which BMW claimed but it was a supremely confident high-speed
performer. With long-travel suspension, superb rider ergonomics and a large fuel
tank, the bike allowed the rider to make use of the motor's abilities. As pilots
of modern sports bikes know all too well, there is no point in having limitless
performance if the riding position causes agony after 50 miles.
There was also a delightful attention to detail which inculcated a sense of
pride in owning a BMW. As an example, the discs were drilled not only for
lightness but also to enhance their performance in wet weather. So far, so good.
What was really clever was that BMW first cadmium plated the disc so that the
drilled holes wouldn't rust and then surface ground the rotors. Knowledgeable
observers stood back, looked at the BMW and nodded sagely at the outstanding fit
and finish. The R90S was expensive but looked to be an out-and-out bargain when
compared with its British and Japanese opposition.
And last but not least, there was the R90S' appearance. In a deliberate attempt
to put the black and dour images behind them, BMW produced their new flagship in
a range of stunning air-brushed colors ranging from burnt orange to a
magnificent air burst grey.
The impact of the styling was immediate and dramatic. Suddenly, for the wealthy,
the R90S became the bike to have. Film stars, Chief Executives and Wall Street
Bankers became BMW owners, and in doing so opened up a whole new market for the
Bavarian bikes.
Yet the really clever thing was that hardcore BMW enthusiasts still stayed with
the factory because of the bike's mechanical prowess: truly, the hardest thing
for any company to pull off.