MOTORCYCLE CLUB IN SAN FRANCISCO
MOTORCYCLE CLUB IN SAN FRANCISCO
1976 BMW R/90s Factory original airhead, last year R/90s model production. Winner 1976 AMA superbike class at Daytona. Perfectly restored black/gray “Silver Smoke” paint job with hand- painted gold pin stripe. Includes factory service manual, factory tool kit, and factory hand operated air pump. Very clean! Come see it at Piston & Chain, 1285 Folsom St., San Francisco.
BMW R90S (from Motorcycle Classics)
Years produced: 1974-1976
Total production: 17,378
Claimed power: 67bhp @ 7,000rpm
Top speed: 125mph
Engine type: 900cc, two-valve, horizontally opposed twin
Weight: 215kg (474lb) wet
Price then: $3,430 (1974)
Built for the long haul
However long BMW builds flat twins, it’s debatable whether there will be another to match the impact the BMW R90S made with its launch in 1974. The half-faired 90S, finished in a stylish smoked-color scheme (gray was the original color, with this bike’s orange following as an option a year later), may have been a sportster only by BMW’s traditionally restrained standards. But with a top speed a shade over 125mph, it was seriously quick by mid-Seventies standards.
The R90S was at its best traveling rapidly over long distances, but there was much more to this bike than sheer speed. Handsome, fine handling, comfortable, well equipped and very expensive, the R90S was arguably the best all-around superbike that money could buy.
The S and its unfaired relation, the R90/6, introduced at the same time, were derived more directly from the previous year’s R75 models. Enlarging the 745cc R75’s bore from 82 to 90mm while retaining the 70.6mm stroke gave a capacity of exactly 900cc. BMW also took the opportunity to make numerous engine mods, including strengthening the bottom end, plus fitting a revised gearshift mechanism and new alternator.
The R90S model differed from the humbler R90/6 by having higher compression (9.5:1 versus 9:1), and a pair of 38mm Dell’Orto carburetors with accelerator pumps in place of the basic model’s 32mm Bings. Those mods helped lift peak power output from the R90/6’s 60bhp to a claimed 67bhp at 7,000rpm — competitive with everything on two wheels except Kawasaki’s awesome 82bhp Z1.
In addition, the S model had a bigger, 6.4-gallon gas tank, twin 200mm front discs instead of just one, plus, of course, that handlebar-mounted fairing with its useful pair of white-faced gauges above the normal speedo and tach. The fairing, tank, front mudguard, side panels and the rear of the slightly stepped dual seat were all visually brought together by that classy paint scheme of subtly changing tones.
One drawback of the R90S paint scheme is that it is almost impossible to retouch, meaning that damaged bodywork must be replaced, rather than repaired, if the bike’s appearance is to be maintained. But BMW’s traditionally excellent standard of finish means that this unrestored R90S still looks remarkably good after 42,000 miles, with just the occasional minor blemish and a slight discoloration of the exhaust pipes.
On the road
It runs very well, too, after you’ve reached inside the fairing to the strangely placed ignition switch, then pressed the button to bring the boxer motor to life with its traditional side-to-side lurch. Despite its raised compression and big Dell’Ortos, the R90S was still as refined and well-behaved as any BMW.
Perhaps the most vivid sensation when riding the R90S now is just how similar the old bike feels to more recent boxers. The tuned S model has a little less low-rev torque than the 90/6 but is still very flexible, its docile power delivery and relaxed cruising ability feeling typically BMW. Even the sloppy gear change would be all too familiar to riders of relatively recent machines.
The R90S’s top speed of slightly over 125mph was impressive by mid-Seventies standards, but perhaps more important was the unmatched ease with which the BMW could sustain an easy high-speed cruise, thanks to its engine’s lack of annoying vibration and to the way the fairing diverted most of the wind from the rider. Aftermarket fairings were available that would do a similar job for other bikes, but no standard rival was as easy to ride fast as the Bavarian bahn stormer.
When you examine the spec sheet it’s no surprise that the elderly bike matches many of its more youthful descendants. Far from being much more powerful, the R100 model that BMW produced almost two decades later, in the early Nineties, had a lower 60bhp peak output. The manufacturer’s official 0-62mph (100km/h) figure put the R90S and 1993-model R100s dead level at 4.8 seconds, and the old warrior more than matched the later boxer on top speed.
