In 1916, two companies,
Gustav Otto's Flugzenmaschinenfabrik (Airplane Factory) and Karl
Rapp's Flugwerke Deutschland, merged to form the Bayerische
Flugzeugwerke (Bavarian Airplane Works). Initially this company
designed and manufactured airplane engines.The Bayerische
Flugzeugwerke was renamed the Bayerische Motoren Werke (Bavarian
Motor Works, BMW) in 1917 by Karl Rapp and Max Friz. Their new
logo, a roundel representing an airplane propeller in the blue
sky, is still used today on all BMW motorcycles and automobiles.
A former Daimler employee, Joseph Popp became BMW's managing
director. Airplane engines, especially a V-12 model, was BMW's
primary output.
With funding from the German air force, BMW began manufacturing
the Fokker DV II one of the best aircraft of that time. However
the fortune of the company turned in 1919 with the end of WWI
and the signing of the Treaty of Versailles. Germany was
forbidden to manufacture airplanes. Reluctantly Max Friz, BMW's
head designer, turned to motorcycle and automobile engines to
sustain the company. Within four weeks, Friz designed the now
legendary horizontally opposed twin cylinder engine known today
as the "boxer" engine.
The first 'boxer' engine, M2B15, was based on
a British Douglas design. The M2B15 proves to be moderately successful, but with
the development of the first light alloy cylinder head, a second more successful
version of the boxer engine evolves. In 1923, the first BMW motorcycle, the R32,
is produced. Using the new aluminum alloy cylinder heads, Friz designs a 486cc
engine with 8.5 hp and a top speed of 60 mph. The engine and gear box form a
single unit. The new engine featured a recirculating wet-sump oiling system
which was very advanced for 1923, as many motorcycle manufacturers still used a
total-loss oiling. BMW used this type of recirculating oiling system until 1969,
showing the advanced design of the times.
The R32 became the foundation for all future
boxer powered BMW motorcycles. BMW oriented the boxer engine with the cylinder
heads sticking out on each side for cooling. Other motorcycle manufacturers,
aligned the cylinders with the frame, one cylinder facing towards the front
wheel and the other towards the back wheel. For example, Harley-Davidson
introduced the model W, a flat twin orientated fore and aft design, in 1919 and
built them through 1923.
Also the R32 incorporated a shaft drive. BMW continued to use shaft drives in
all their motorcycles until the introduction of the F650 in 1994. The F650
series is the only model BMW that does not use shaft drive.
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In 1935, BMW introduced the first production motorcycle to use telescopic forks.
Also, by this time the benefits of overhead cams were known. Higher revs could
be obtained before the onset of valve float. However, the basic boxer design did
not lend itself to overhead cams. To obtain the benefits of overhead cams
without overly increasing the engine width, BMW incorporated a system that was
so advanced for its racing bikes that it resurrected it many decades later in
the R1100RS oilhead. The system was two cams in the head operating short push
rods via rocker arms.
In 1937, Ernst Hene rode a supercharged 500cc
overhead cam BMW 173.88 MPH, setting a world record that stood for 14 years.
Ernst Hene died at the age of 100 in 2005.
World War II - 1960
The end of World War II found BMW in ruins. Its plant outside of Munich was
destroyed by allied bombing. An entire assembly line in the Eisenach facility
was dismantled by the Soviets as war booty and sent it back to Russia where it
was reassembled in Irbit, Russia to make Ural motorcycles. After the war the
terms of Germany's surrender forbid BMW from manufacturing motorcycles. Most of
BMW's brightest engineers were taken to the US and Russia to continue their work
on jet engines which BMW produced during the war.
When the ban on the production of motorcycles was lifted, BMW had to start from
scratch. There were no plans, blueprints, or schematic drawings. Company
engineers had to use surviving prewar motorcycles to create new plans. The first
postwar BMW motorcycle was produced in 1948. In 1949, BMW produced 9,200 units.
By 1950 production surpassed 17,000 units.
In 1951, BMW introduced the first sporting motorcycle, the R68. It was a 594cc
single cam engine with 7.5:1 compression ratio and venturi throat sizes of 26mm
and larger valves. As the 1950's progressed, motorcycle sales plummeted. In
1957, three of BMW's major German competitors went out of business. In 1954, BMW
produced 30,000 motorcycles. By 1957, that number was less than 5,500. However,
by the late 50's, BMW exported 85% of its boxer twin powered motorcycles to the
United States. At that time, Butler & Smith, Inc. was the exclusive U.S.
importer of BMW.
On June 8, 1959, John Penton rode a BMW R69 from New York to Los Angeles in 53
hrs. 11 min. setting a record. The previous record of 77 hrs. 53 min. was set by
Earl Robinson on a 45 cubic inch Harley-Davidson.
1960 - 1984
Although U.S. sales of BMW motorcycles were strong, BMW was in financial
trouble. The combination of selling off its aircraft engine division and
obtaining financing with the help of Herbert Quandt, BMW was able to survive.
Part of the turn around in the company's fortunes was BMW's increasing success
of it automotive division. Since the beginning of the motorcycle manufacturing,
BMW periodically introduced single-cylinder models. In 1960, BMW offered the
last of these, the R27. Most of BMW's offerings were still designed to be used
with sidecars. By this time sidecars were no longer a consideration of most
riders, people were interested in more sporty motorcycles.
1984 - 2005
In the early 1983 BMW introduced an 1000cc, in-line 4 cylinder, water
cooled engine to the European market, the K100. In 1984, those models
were introduced to the US market. It was assumed that this new engine
would not only be the basis for a new models, it would be the
replacement for the aging boxer flat twin engine. However, demand for
the boxer did not wane with the introduction of this new engine and
associated models. And the demand of the new engine models was much less
than BMW anticipated. Therefore, BMW continued to produce boxer models.
In 1985 BMW produced a 750cc, three cylinder version of the new 4
cylinder water cooled engine. The 750cc was counterblanced, therefore
smoother. The R100RT, boxer powered sport touring bike with a monolever
rear suspension was reintroducted in 1987. BMW introduced new rear
suspension on the K bikes, a double joined single sided swing arm. In
1989, BMW introduced their version of a full faring sport bike, the K1.
It was based upon the K100 engine with 4 valves per cylinder. Output was
near 100 bhp. Also in 1988, BMW introduced ABS on their motorcycles. A
first in the motorcycle industry. ABS became standard on all BMW K
models.
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Model names
BMW motorcycles are named according to a three-part code: <engine type>
<approximate engine volume> <style information>
BMW R1200
Thus, an R1150RT has
an R series engine
approximately 1150 cc of engine displacement
"RT" styling Engine types
There are currently three lines of BMW motorcycles:
F series (singles & twins)
R series
K series
The series differ primarily in the class of engine that each uses.
F series singles
The F series singles are built around a 4-stroke, single cylinder Rotax engine.
These bikes tend to be light, economical and durable.
R series
The R series are built around a horizontally opposed flat-twin (or boxer)
engine. As the engine is mounted transversally across the bike, and the heads
protrude well beyond the frame of the bike, R series motorcycles are quite
visually distinctive. Originally R series bikes had air-cooled heads ("air
heads"), but are now produced only with oil-cooled heads.
K series
The K series are built around liquid cooled, inline engines with three (K75) or
four (K100, K1100, K1200) cylinders. Unusually for motorcycles, the engine is
longitudinal: the crankshaft is in line with the direction of motion. Also, the
cylinders are banked over, parallel to the ground. This causes some to
incorrectly call the configuration a Flat-4.
Engine Volume
Engine volume, as specified in the model number, is approximate.
Style
Every bike has one or two of the following primary designations:
C - cruiser
S - sport
T - touring
R - road
G - offroad / adventure
Additionally, a bike may have zero or more of the following modifiers in its
name:
L - luxury
P - police
This article is licensed under the GNU Free Documentation
License
Any corrections or more information on these motorcycles will be kindly appreciated.