1977 BMW R100RS

Setting the stage
BMW motorcycles have always been about eating miles with style and comfort. Back
in the 1960s, however, they were quickly coming to be regarded as — dare we say
it — an old man’s motorcycle. Articles in period magazines often referred to BMW
as “The Rolls Royce of Motorcycles.” Though it was a compliment, it was understood
that Rollers cost a mint, were staid and quiet, and were owned by old men.

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been made standard across the line, and the ovoid valve covers had been replaced
by rectangular units.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.

Additionally, the RS’s glass headlight cover carried a set of five, oddly spaced
horizontal orange lines. It was suggested they were metallic and had a defogging
function, but when I asked a source from BMW’s importer, Butler & Smith, about this,
he chuckled and said, “They were purely for styling. At the introduction, when some
journalists were around, I made up the thing about defogging–and apparently some
of them believed me!”

Aboard the BMW R100RS
The key is located up on the dashboard above the speedometer and tachometer, flanked
by the voltmeter and clock. The clutch demands a strong pull, and shifting — a sore
point back in the day — is slow, as the rider has to pause during the first two
shifts; the gears align slowly because of the engine’s heavy flywheel, and selecting
those lower gears produces an audible “clunk” from the transmission’s innards.

Testers generally had good things to say about the stock suspension. Cycle
said that it was “a genuinely good high-speed handler.” And Cycle World said
“the suspension is firm enough to give complete control, yet supple enough to soak
up undulations and ripples.” They concluded: “One has to look long and hard to find
a motorcycle that suspends like the BMW for all-around riding conditions.” Cycle
added that “the swingarm, front suspension and downtube modifications have produced
a genuinely good high-speed handler.” However, the stock suspension is a bit soft.
Push the BMW R100RS hard on the street and the rear brake pedal on the right side
and the sidestand foot on the left begin to drag. The fork will also dive several
inches under heavy braking.

Because of their driveshafts and soft suspensions, BMWs of the day need to be ridden
smoothly. Run the RS hot into a corner on the gas and the driveshaft-induced torque
reaction causes the rear of the bike to rise and extend its suspension. Brake hard
and close the throttle and the bike will drop abruptly because springing and damping
are not stern enough to deal with the loads. Release the brakes or get on the gas
and the bike will pop up again. There’s not much leverage with the RS’s stubby handlebar,
so the rider has to use body position to weight it for turns. To survive, the Beemer
rider learns to downshift before the turn, use engine braking — and the brakes minimally
— maintain a sweeping line with fine throttle and steering adjustments, and then
roll ‘er on out with midrange. This approach allows Beemer riders to go very fast
indeed through turns, and stay with riders on much more powerful bikes.

Riding comfort
While the jackets and pants of riders on unfaired bikes snap and flap in the breeze,
the BMW rider’s garments remain quiet. This gives the BMW R100RS rider a look of
unhurried control and coolness, no matter what his speed. Though the fairing works
well, one universal complaint is that the RS windshield directs the wind blast right
into the collar area, which generates a lot of noise for those wearing a full-face
helmet. In rainy weather, so long as he keeps moving, only the rider’s helmet, shoulders
and feet get wet. Heat funneled from the cylinders keeps the feet warm in cool weather,
but, for some, too warm in the heat. Some riders remove the lowers in warmer weather.

Cycle World thought the handlebars were “just not right … [they] angle the
wrists unnaturally and make the ride tiring after about a 50-mile distance.” Of
course, such vagaries are a personal thing. I frequently ride 300-500 miles in a
day on my 1981 BMW R100RS, and other than a knot in my neck, I find the tucked-in
crouch quite comfortable.

As for torque, Cycle stated it “has so much urge that you’ll seldom explore
above 6,500rpm. It is the Roll-on King of the Universe.” Personally, I find that
vibration will sometimes put a hand or arm to sleep at around 70mph in top gear,
but the mirrors generally remain clear. Cycle concluded: “It doesn’t devour
distance so much as it transcends it, and there is no sense of deterioration or
loss of freshness as the miles stream by below.”

The second-edition BMW R100RS
The first-edition BMW R100RS, with many updates focusing on brakes and shifting,
and those wonderful cast “snowflake” wheels, lasted through the pearl-white Last
Edition models of 1984 when BMW dropped its R100 line and relied primarily upon
its K-bike triples and fours to carry it forward. By 1986, the R65 and R80 were
the only air-cooled BMW twins left. But the K-bikes were not as popular as BMW had
hoped, and there was a worldwide clamor to bring back the 980cc twin.

To assuage these riders, BMW re-introduced several additional models including the
R100RS, R100GS and R100RT, first to Europe in 1987 and then to the
United States the following year. They were based upon the improved monoshock frame
and single-sided swingarm of the R80 with updated brakes, so the 1988 BMW R100RS
was a functional step forward, but other touches didn’t sit well with purists as
its character had been changed. The fairing’s center, lower section had reverted
to the original open grillwork of the earliest models, which was fine, but the front
fender, side covers and rear cowling had all been abbreviated and softened. While
the pipes had pleasing, sweeping lines, their ends were capped except for a small
hole through which only limp sound emerged. Though the tank looked the same, it
lost about a gallon in capacity to clear equipment sitting under it. More importantly,
the engine’s character had been changed, tuned more for torque than high-end power.
Though the quarter-mile times were nearly identical to those of the 1977 model (Cycle
World got 13.3 seconds at 98mph), and the power was more usable for most
riders, the RS was clearly no longer a Superbike, and the model was finally dropped
in 1993. MC

Resources
Clubs and Owners Groups
•
BMW Motorcycle Owners of America
•
Vintage BMW Motorcycle Owners
• The
Internet BMW Riders

BMW Parts
• Blue
Moon Cycle
• Boxerworks
•
Autobahn Craftworks

Read more about the other motorcycles mentioned in this article:
• BMW R90S
• BMW R100GS