BMW's motorcycle history began in 1921 when the company commenced manufacturing engines for other companies. Motorcycle manufacturing now operates under the BMW Motorrad brand. BMW (Bayerische Motoren Werke AG) introduced the first motorcycle under its name, the R32, in 1923.
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BMW began in 1916 as a reorganization of Rapp Motorenwerke, an aircraft engine manufacturer that began production before World War I. With the Armistice, the Treaty of Versailles banned the German air force and the manufacture of aircraft in Germany, so the company turned to making air brakes, industrial engines, agricultural machinery, toolboxes and office furniture and then to motorcycles and cars.
In 1921, BMW began manufacture of its M2B15 flat-twin engine. Designed by Max Friz for use as a portable industrial engine, the M2B15 was largely used by motorcycle manufacturers, notably Victoria of Nuremberg, and Bayerische Flugzeugwerke in their Helios motorcycle.[1] Friz was also working on car engines.
BMW merged with Bayerische Flugzeugwerke in 1922, inheriting from them the Helios motorcycle and a small two-stroke motorized bicycle called the Flink.[1] In 1923, BMW's first "across the frame" version of the boxer engine was designed by Friz. The R32 had a 486 cc (29.7 cubic inches) engine with 8.5 hp (6.3 kW) and a top speed of 95 to 100 km/h (59 to 62 mph).[2] The engine and gearbox formed a bolt-up single unit. At a time when many motorcycle manufacturers used total-loss oiling systems, the new BMW engine featured a recirculating wet sump oiling system with a drip feed to roller bearings. This system was used by BMW until 1969, when they adopted the "high-pressure oil" system based on shell bearings and tight clearances, still in use today.
The R32 became the foundation for all future boxer-powered BMW motorcycles. BMW oriented the boxer engine with the cylinder heads projecting out on each side for cooling as did the earlier British ABC. Other motorcycle manufacturers, including Douglas (motorcycles) and Harley-Davidson, aligned the cylinders with the frame, one cylinder facing towards the front wheel and the other towards the back wheel.
The R32 also incorporated shaft drive. BMW continued to use shaft drive in all of its motorcycles until the introduction of the F650 in 1994, which featured chain drive.
In 1937, Ernst Henne rode a supercharged 500 cc (31 cubic inches) overhead camshaft BMW 173.88 mph (279.83 km/h), setting a world record that stood for 14 years.
During World War II the Wehrmacht needed as many vehicles as it could get of all types and many other German companies were asked to build motorcycles. The BMW R75, a copy of a Zündapp KS750, performed particularly well in the harsh operating environment of the North African Campaign. Motorcycles of every style had performed acceptably well in Europe, but in the desert the protruding cylinders of the flat-twin engine performed better than configurations which overheated in the sun, and shaft drives performed better than chain-drives which were damaged by desert grit.
So successful were the BMWs as war-machines that the U.S. Army asked Harley-Davidson, Indian and Delco to produce a motorcycle similar to the side-valve BMW R71. Harley copied the BMW engine and transmission — simply converting metric measurements to inches — and produced the shaft-drive 750 cc (46 cubic inches) 1942 Harley-Davidson XA.[3]
The end of World War II found BMW in ruins. Its plant outside of Munich was destroyed by Allied bombing. The Eisenach facility while badly damaged was not totally destroyed and tooling and machinery was safely stored nearby. The facility was not dismantled by the Soviets as reparations and sent back to the Soviet Union where it was reassembled in Irbit to make IMZ-Ural motorcycles as is commonly alleged. The IMZ plant was supplied to the Soviets by BMW under license prior to the commencement of the Great Patriotic War. After the war the terms of Germany's surrender forbade BMW from manufacturing motorcycles. Most of BMW's brightest engineers were taken to the US and the Soviet Union to continue their work on jet engines which BMW produced during the war.
When the ban on the production of motorcycles was lifted in Allied controlled Western Germany, BMW had to start from scratch. There were no plans, blueprints, or schematic drawings because they were all in Eisenach. Company engineers had to use surviving pre-war motorcycles to copy the bikes. The first post-war BMW motorcycle in Western Germany, a 250 cc R24, was produced in 1948. The R24 was based on the pre-war R23, and was the only postwar West German BMW with no rear suspension. In 1949, BMW produced 9,200 units and by 1950 production surpassed 17,000 units.
BMW boxer twins manufactured from 1950 to 1956 included the 500 cc models R51/2 and 24 hp (18 kW) R51/3, the 600 cc models 26 hp (19 kW) R67, 28 hp (21 kW) R67/2, and R67/3, and the sporting 35 hp (26 kW) 600 cc model R68. All these models came with plunger rear suspensions, telescopic front forks, and chromed, exposed drive shafts. Except for the R68, all these twins came with "bell-bottom" front fenders and front stands.
The situation was very different in Soviet-controlled Eastern Germany where BMW's sole motorcycle plant in Eisenach was producing R35 and a handful of R75 motorcycles for reparations. This resulted in one BMW motorcycle plant existing in Eisenach between 1945 and 1948 and two motorcycle companies existing between 1948 and 1952. One was a BMW in Munich in Western Germany (later the German Federal Republic) and the other in Soviet controlled Eisenach, Eastern Germany (later the German Democratic Republic), both using the BMW name. Eventually in 1952. after the Soviets ceded control of the plant to the East German Government, and following a trademark lawsuit, this plant was renamed EMW (Eisenacher Motoren Werke). Instead of BMW's blue-and-white roundel, EMW used a very similar red-and-white roundel as its logo.[4] No motorcycles made in East Germany after World War II were manufactured under the authority of BMW in Munich as there was no need for an occupying power to gain such authority. After the collapse of the Iron Curtain many EMW models have made their way to the USA. It is possible to find find restored R35 motorcycles today parts of which are EMW and parts of which are BMW as many parts are interchangeable, making authentic identification quite difficult because all BMW R35 motorcycles were produced in Eisenach until 1952, when they became EMW.
As the 1950s 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 1950s, 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.
In 1955, BMW began introducing a new range of motorcycles with Earles forks and enclosed drive shafts. These were the 26 hp (19 kW) 500 cc R50, the 30 hp (22 kW) 600 cc R60, and the 35 hp (26 kW) sporting 600 cc R69.
On June 8, 1959, John Penton rode a BMW R69 from New York to Los Angeles in 53 hours and 11 minutes, slashing over 24 hours from the previous record of 77 hours and 53 minutes set by Earl Robinson on a 45 cubic inch (740 cc) Harley-Davidson.
Although U.S. sales of BMW motorcycles were strong, BMW was in financial trouble. Through the combination of selling off its aircraft engine division and obtaining financing with the help of Herbert Quandt, BMW was able to survive. The turnaround was thanks in part to the increasing success of BMW's automotive division. Since the beginnings of its motorcycle manufacturing, BMW periodically introduced single-cylinder models. In 1967, 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 sportier motorcycles.
The 26 hp (19 kW) R50/2, 30 hp (22 kW) R60/2, and 42 hp (31 kW) R69S marked the end of sidecar-capable BMWs. Of this era, the R69S remains the most desirable example of the dubbed "/2" ("slash-two") series because of significantly greater engine power than other models, among other features unique to this design.[5]
For the 1968 and 1969 model years only, BMW exported into the United States three "US" models. These were the R50US, the R60US, and the R69US. On these motorcycles, there were no sidecar lugs attached to the frame and the front forks were telescopic forks, which were later used worldwide on the slash-5 series of 1970 through 1973. Earles-fork models were sold simultaneously in the United States as buyers had their choice of front suspensions.
In 1970, BMW introduced an entirely revamped product line of 500 cc, 600 cc and 750 cc displacement models, the R50/5, R60/5 and R75/5 respectively and came with the "US" telescopic forks noted above. The engines were a complete redesign. The roller and ball-bearings in the bottom end had been replaced by shell-type journal bearings similar to those used in modern car engines. The camshaft, which had been at the top of the engine, was placed under the crankshaft, giving better ground clearance under the cylinders while retaining the low centre of gravity of the flat-twin layout. The new engine had an electric starter, although the traditional gearbox-mounted kick starter was retained. The styling of the first models included chrome-plated side panels and a restyled tank, these have been called "toaster" models because of the tank's resemblance to a kitchen toaster.
The /5 series was given a longer rear swingarm, resulting in a longer wheelbase. This improved the handling and allowed a larger battery to be installed. These were called the long wheelbase, LWB, 1973½ versions.
The /5 models were short-lived, however, being replaced by another new product line in 1974. In that year the 500 cc model was deleted from the lineup and an even bigger 900 cc model was introduced, along with improvements to the electrical system and frame geometry. These models were the R60/6, R75/6 and the R90/6. In 1973 a supersport model, the BMW R90S, was introduced. In 1975, the kick starter was finally eliminated. In addition to "/" or "slash" models, other Airhead models such as the G/S (later, GS) and ST also have dedicated followings within BMW circles, while others favor certain earlier models like /5 "toasters." Each has its merits which owners will freely debate with enthusiasm.
In 1977, the product line moved on to the "/7" models. The R80/7 was added to the line. The R90 (898 cc) models, "/6" and R90S models were replaced by updated versions with a new 1,000 cc; engine, the R100/7, the R100S and the new super sport model the R100RS with a full fairing. This sleek model, designed through wind-tunnel testing, produced 70 hp (51 kW) and had a top speed of 200 km/h (124 mph).[6] The R100RS had a shorter rear end ratio to overcome the higher wind resistance of the full fairing. Many period motorcycle tests in Germany (Das Motorrad) indicated it was actually slightly slower than the R100S with only 65 hp. In 1978, the R100RT was introduced into the lineup for the 1979 model year, as the first "full-dress" tourer, designed to compete in this market with the forthcoming Honda Gold Wing.
In 1979, the R60 was replaced with the 650 cc R65, an entry-level motorcycle with 48 hp (36 kW) that had its very own frame design. Due to its smaller size and better geometrics, front and rear 18-inch (460 mm) wheels and a very light flywheel, was an incredibly well-handling bike that could easily keep up and even run away from its larger brothers when in proper hands on sinuous roads. BMW added a variant in 1982: the R65LS, a "sportier" model with a one-fourth fairing, double front disc brakes, stiffer suspension and different carburettors that added 5 hp (4 kW). A short-stroke version of the R65, the 450 cc R45 appeared in some markets.
In early 1983, BMW introduced a 1,000 cc, in-line four-cylinder, water-cooled engine to the European market, the K100. The K series comes with a simplified and distinctive rear suspension, a single-sided swingarm. (In 1985 the traditionally powered boxer R80RT touring bike received this monolever rear suspension system and in 1987 the R100RT received it).
In 1985, BMW introduced a 750 cc three-cylinder version, this one smoothed with another first, a counterbalance shaft.
In 1986, BMW introduced an electrically adjustable windshield on the K100LT.
In 1988, BMW introduced ABS on its motorcycles. ABS became standard on all BMW K models. In 1993 ABS was first introduced on BMW's boxer line on the R1100RS. It has since become available as an option on the rest of BMW's motorcycle range.
In 1989, BMW introduced its version of a full-fairing sport bike, the K1. It was based upon the K100 engine, but now with four valves per cylinder. Output was near 100 hp (75 kW).
In 1995, BMW ceased production of airhead 2-valve engines and moved its boxer-engined line completely over to the 4-valve oilhead system first introduced in 1993.
During this period, BMW introduced a number of motorcycles including:
The R1200C, produced from 1997 to 2004, was BMW Motorcycles only entry into the Cruiser market. At the other end of the model lineup, the C1, produced from 2000 to 2002, was an enclosed scooter, the only scooter to be offered for sale by BMW.
On 25 September 2004, BMW globally launched a radically redesigned K Series motorcycle, the K1200S, containing an all new in-line four-cylinder, liquid-cooled engine featuring 123 kW (165 hp).[7] The K1200S was primarily designed as a Super Sport motorcycle, albeit larger and heavier than the closest Japanese competitors. Shortly after the launch of the K1200S, problems were discovered with the new power plant leading to a recall until the beginning of 2005, when corrective changes were put in place.
In the years after the launch of K1200S, BMW has also launched the K1200R naked roadster, and the K1200GT sport tourer, which started to appear in dealer showrooms in spring (March–June) 2006. All three new K-series motorcycles are based on the new in-line four-cylinder engine, with slightly varying degrees of power. In 2007, BMW added the K1200R Sport,[8] a semi-faired sport touring version of the K1200R.
In October 2008, BMW launched three new 1,300 cc K-series models: the K1300R, K1300S and K1300GT.[9] The K1300 models feature an increase in engine capacity of 136 cc, an increase in power to 175 hp (130 kW), newly styled fairings and a new exhaust system.
In 2011, BMW launched two six-cylinder, 1,600 cc, K1600GT and K1600GTL motorcycles, the former intended as a sport-tourer and the latter as a luxury touring model. The engine produces 160 hp (120 kW) and 129 lb·ft (175 N·m). They also offer adaptive headlights, traction control, ABS, tire pressure monitors, and a variety of sound systems.
In 2004, bikes with the opposed-twin-cylinder "boxer" engine were also revamped. The new boxer displacement is 1,170 cc (71 cubic inches). The engine is more powerful, and all of the motorcycles that use it are lighter than their predecessors.
The first motorcycle to be launched with this updated engine was the R1200GS dual-purpose motorcycle. The R1200RT tourer and R1200ST sports tourer followed shortly behind. BMW then introduced the 175 kg (390 lb), 105 kW (141 hp) HP2 Enduro, and the 223 kg (490 lb), 100 hp (75 kW) R1200GS Adventure, each specifically targeting the off-road and adventure-touring motorcycle segment, respectively. In 2007, the HP2 Enduro was joined by the road-biased HP2 Megamoto fitted with smaller alloy wheels and street tyres.
In 2006, BMW launched the R1200R and the R1200S, which is rated at 90 kW (121 hp) @ 8,250 rpm.
BMW has also paid attention to the F Series in 2006. It lowered the price on the existing F650GS and F650GS Dakar, and eliminated the F650CS to make room in the lineup for the all-new F800 Series. The new motorcycles are powered by a parallel twin engine, built by Rotax. They feature either a belt drive system, similar to the belt drive found on the now defunct F650CS, or chain drive. Initially, BMW launched two models of the new F800 Series, the F800S sport bike and the F800ST sport tourer; these were followed by F650GS and F800GS dual-purpose motorcycles, both of which use the 798 cc engine despite the different names.[10]
In October 2006, BMW announced the G series of offroad style motorcycles co-developed with Aprilia. These are equipped with an uprated single-cylinder water-cooled 652 cc fuel-injected engine producing 53 hp (40 kW), similar to the one fitted to the single-cylinder F650GS, and are equipped with chain drive. There are three models in the series, all produced for BMW by Aprilia in their North Italian Scorzè Plant, each focused on a slightly different market:
In some markets the single-cylinder F650GS has been rebranded as the G650GS.[11]
First was the 175 kg (390 lb), 105 hp (78 kW) HP2 Enduro, followed by the road-biased HP2 Megamoto fitted with smaller alloy wheels and street tyres in 2007.
In April 2007, BMW announced its return to competitive road racing, entering a factory team with a "Sport Boxer" version of the R1200S to four 24-hour endurance races.[12] In 2008 they released this as the HP2 Sport.
The S1000RR is a sport bike launched to compete in the 2009 Superbike World Championship.[13] It is powered by a 999 cc (61 cu in) inline-four engine producing 193 bhp (144 kW).
In July 2007, it was announced that BMW had signed a contract to acquire Husqvarna Motorcycles, including its production facilities and staff, from Italian manufacturer MV Agusta.[14][15]
There are currently four lines of BMW motorcycles:
The series differ primarily in the class of engine that each uses.
The F Series of single-cylinder BMW motorcycles was first launched in 1994, as the F650, and was built by Aprilia around a carbureted 650 cc four-stroke, four-valve, single piston engine, and chain drive. The mission for the F 650 was to provide an entry level BMW motorcycle. In 2000, the F650 was redesigned, now with fuel injection, and labeled the F650GS. An off-road focused F650 Dakar model was also launched that year. 2002 saw the addition of the F650CS 'Scarver' motorcycle to the line up. The Scarver was different from the F650GS variants in that it utilized a belt drive system opposed to a chain, had a much lower seat height, and was intended for on-road use. All F650 motorcycles produced from 2000 to 2007 used a 652 cc engine built in Austria by Rotax and were built by BMW in Berlin.
In late 2006, the G series of offroad biased bikes motorcycles was launched using the same 652 cc engine fitted to the F650GS, although that engine is no longer manufactured by Rotax. The latest version of the 652cc single engine fitted in the new G650GS is now produced in Berlin after 2 years production in Loncin, China.
In November 2007, the G450X sport enduro motorcycle was launched using a 450 cc single-cylinder engine. The G450X contained several technological improvements over the Japanese off road racing motorcycles but the most unique and significant was the use of a single pivot point for the drive sprocket and the swing arm. This unusual configuration allowed for a very tense drive chain with no slop and eliminated acceleration squat. The former benefit saves on chain and sprocket wear and the later allows for a more consistent drive geometry and fully available rear suspension travel during heavy acceleration.
In mid 2006, The F Series added two new motorcycles to the lineup, the F800S sports bike and F800ST sports tourer, both which use an 798 cc parallel-twin engine built by Rotax. Both motorcycles also feature a belt drive system similar to what was in use on the F650S. In 2007 the single-cylinder F650GS was replaced with the twin-cylinder F800GS and F650GS models. The latter uses a de-tuned version of the 798 cc engine fitted to the F800GS,[10] marking a departure from BMW's naming convention.
The R series are built around a horizontally opposed flat-twin boxer engine. As the engine is mounted with a longitudinal crankshaft, the cylinder heads protrude well beyond the sides of the frame, making the R series motorcycles visually distinctive. Originally, R series bikes had air-cooled heads ("air heads"), but are now produced only with oil-cooled heads ("oilheads" and "hexheads").
Photo of Four different BMW "heads": How do you tell the different BMW valve covers ("heads") since 1970 apart? The "airhead" cover on a 1973 R75/5 is upper left. The first "oilhead" cover, introduced in model year 1993 in Europe and 1994 in the US, is upper right. The "oilhead" cover on an R1150RT, with two spark plugs per cylinder, is lower left. The latest "hexhead" cover, with an optional valve cover protector, on an R1200RT, is lower right.
Photo of Pre-1970 valve cover: A common valve cover from 1952 to 1969 on models R50, R60, R50/2, R60/2, R51/3, R67, R67/2, R67/3 had six fins. The R50S, R68, R69, and R69S of this period had two-fin valve covers.
The K series BMW's have water-cooled engines of three (K75), or four (K100, K1100, K1200, K1300), or six (K1600) cylinders. Until 2005, although currently in use on the K1200LT, the engine was longitudinally mounted, laid out on its left side with the cylinder heads on the left and the crankshaft on the right. It is called the "Flying Brick" because of the appearance of this layout. Sales did not meet BMW's expectations, and production ceased with the 1993 model. In 2004, BMW introduced a new four-cylinder water-cooled engine that transverses the chasis and is tilted forward 55 degrees. The BMW K75, three-cylinder, models were produced from 1985 to 1996.
The first K-series production bike was the K100, which was introduced in the 1983. In 1988 BMW introduced the K1 which had the Bosch Motronic fuel injection system.
From 1985 to 1996, the K75 740 cc three-cylinder engine was produced.
In 1991 BMW increased the displacement of the K100 from 987 cc to 1,097 cc and the model designation became the K1100. The K1100LT was the first with the new engine displacement. In 1998 BMW increased the size again to 1,170 cc. This upgraded flat four engine appeared in the K1200RS. This engine is still in production for the K1200LT.
The later K1200 engine is a 1,157 cc transverse inline-four, announced in 2003 and first seen in the 2005 K1200S. The new engine generates 123 kW (165 hp) an is tilted forwards 55 degrees. It is 43 cm (17 in) wide, giving the bikes a very low center of mass without reducing maximum lean angles.[16]
In October 2008, BMW announced the new K1300GT, K1300S and K1300R models, all of which feature a larger capacity 1293 cc engine producing up to 175 hp (130 kW). The new engine produces maximum power output 1,000 RPM lower than the previous engine, produces more torque due in part butterfly flap fitted in the exhaust.
In 2011, BMW launched the K1600 range—the K1600GT and K1600GTL—featuring a new 1,649 cc (100.6 cu in) straight-six engine, which is mounted transversely across the chassis.[17] The engine is angled forward by 50°.[18] The engine was originally used on the Concept 6, a concept bike that was shown at the 2009 EICMA Milan Motor Show.[19] BMW claims that the engine at 560 mm (22 in) wide, just 67 mm (2.6 in) wider than the K1300 engine,[18] is the narrowest six-cylinder engine ever produced. Cylinder bore is 72.0 mm (2.83 in) and the distance between cylinder centres 77 mm (3.0 in).[18] The camshaft is hollow, with cam lobes pressed on, which saves around 2 lb (0.91 kg).[20] The engine has electronic throttle control and multiple drive modes which can be set according to road conditions.
BMW motorcycles are named according to a three-part code made up of the engine type, approximate engine volume, and styling information (e.g., sport, sport touring, luxury touring, etc.). The three parts are separated by blanks.[21][22][23]
Engine type
Engine displacement in cc
Styling suffix designations:
Additionally, a bike may have the following modifiers in its name:
Examples: K1200S, R1200RT, F650GS, R1150RSL, K1200LT, K1200LT-C, R1200RT-P, R1200RSA.
Prior to the introduction of the K100 series and the R1100 series motorcycles, the letter prefix was always the same, and the numbers were either based on displacement, as mentioned above, or were just model numbers.
The first BMW monolever suspensions appeared in 1980 on the then-new R80G/S range. It had a single universal joint immediately behind the engine/gear-box unit. This system was later included on updated versions of the K & R Series.
Paralever is a further advance in BMW's single-sided rear suspension technology (photo right). It decouples torque reaction as the suspension compresses and extends, avoiding the tendency to squat under braking and reducing tyre chatter on the road surface. It was introduced in 1988 R80GS and R100GS motorcycles.
In 2005, along with the introduction of the "hexhead", BMW inverted the Paralever and moved the torque arm from the bottom to the top of the drive shaft housing (photo right). This reduces underhang of components and tends to increase ground clearance in right lean.
It is believed that the term Paralever was developed due to the appearance of a parallelogram shape between the four items making up the rear suspension (rear drive, drive shaft, transmission, and lower or upper brace). Other motorcycle manufacturers have patented versions of this system, including Arturo Magni for MV Agusta and Moto Guzzi's Compact Reactive Shaft Drive.
In 1935, BMW fitted a hydraulically damped telescopic fork to its motorcycles. BMW still uses telescopic forks today on its F-series, G-series and HP motorcycles. The R-series and K-series use the Telelever and the Duolever front suspensions.
Englishman Ernest Earles designed a unique triangulated fork that resists the side-forces introduced by sidecars (unlike telescopic forks).[24][25][26] BMW fitted the Earles fork to all its models for 14 years from 1955. In the event, this was the year that use of sidecars peaked and quickly fell off in most European markets (e.g. the UK) but the Earles fork system was well liked by solo riders too. It causes the front end of the motorcycle to rise under braking — the reverse of the action of a telescopic fork. The mechanical strength of this design sometimes proved to be a weakness to the rest of the motorcycle, since it transfers impact pressure to the frame where damage is more difficult and expensive to correct.
The Telelever system was developed by Saxon-Motodd in Britain in the early 1980s. The Telelever is a unique front fork, where the shock absorber is located between and behind the two primary tubes attached to a telelever arm.
This system both lowers unsprung weight as well as decouples wheel placement function of the forks from the shock absorption function - eliminating brake dive and providing superior traction during hard-braking situations. This system improves comfort and stability considerably while providing excellent and sporty handling.
In the photo to the left you can see the Telelever suspension unit. The two fork tubes provide no damping or suspension. The front of the light gray "A-arm" can be seen reaching forward from the side of the engine to the (hidden) cross brace between the fork tubes.
In 2004, BMW announced the K1200S, incorporating a new front suspension based upon a design by Norman Hossack.[27] BMW recognised this fact but paid Hossack no royalties. BMW named its new front suspension the Duolever. As of 2009, the Duolever is on the K1300S, K1300R and K1300GT.
The official BMW Motorrad explanation of the duolever is:[28]
The Duolever front wheel suspension is kinematically regarded as a square joint, in which two trailing links made of forged steel are attached via rolling bearings to the frame. These trailing links, which visually resemble a conventional fork, guide the extremely torsionally rigid wheel carrier made of aluminium permanent mold casting. A central strut, which adjusts the suspension and damping, is linked to the lower of the two trailing links, and rests against the frame.
A trapezoidal shear joint mounted to the control head and the wheel carrier is coupled with the handlebar. This shear joint transmits the steering movements. Thus, the Duolever design in contrast to the telefork does not need sliding and fixed tubes. At the same time, it decouples the steering as well as the damping more consistently than the proven telelever.
The advantage of this front wheel suspension on the motorcycle market at present is its torsional rigidity. The BMW Motorrad Duolever front wheel suspension is not influenced by negative forces in the same manner as a conventional telefork whose fixed and take-off tubes twist laterally as well as longitudinally during jounce/rebound and steering. Its two trailing links absorb the forces resulting from the jounce/rebound and keep the wheel carrier stable. Thus, any torsioning is excluded and the front wheel suspension is very precise. The steering commands of the rider are converted directly and the feedback from the front wheel is transparent in all driving conditions.
A kinematical anti-dive effect is additionally achieved, just as for the Telelever, due to the arrangement of the trailing link bearings. While a conventional telefork during strong braking manoeuvres jounces heavily or locks, the Duolever still has sufficient spring travel remaining in this situation and therefore the rider can still brake into the corner extremely late yet directionally stable.
The obstacle-avoidance manoeuvre of the front wheel when riding over uneven surfaces can be converted with the Duolever similar to the behaviour of a telefork. In connection with the low unsprung masses and the small breakaway forces of the system, this results in more sensitive and comfortable response characteristics.
Admirers of vintage BMW motorcycles are growing rapidly in number. As time marches on, that which BMW enthusiasts consider "vintage" is amended. Pre-war BMWs are the most coveted, as demonstrated during the Gooding & Company auction in California in October 2006, when a 1925 BMW R32 sold for $77,000.
Plunger-frame models from the 1950s are the next most coveted, and then "Slash-2" variants from 1955 to 1969. In recent years, the "Slash-5" models from the 1970 to the 1973 model years have begun to join that exclusive club. Prices for historic BMW models have been rising quickly, fed in part by motorcycle auctions such as the massive Mid-America Auction held each January in Las Vegas, Nevada.
Opinions as to the treatment of vintage motorcycle varies according to their condition and their owners' tastes. First preference tends to be for preserving the original machine if it is in reasonably good condition. Second preference is to do limited restoration, maintaining as much of the original fabric as possible. Third, when dealing with a machine in poor condition, is so-called frame-up restoration. In the latter case, the motorcycle is completely disassembled and each individual part is refurbished, and then the motorcycle is reassembled hewing as much as possible to the original design, but sometimes using modern replacement parts, such as stainless steel, or plating parts that were originally not plated. At the extreme end of restoration is the "concours" restoration in which only original parts are used and work is done with an obsession for originality in every minor detail. Unlike many other motorcycle brands, parts for vintage BMWs, though expensive, are obtainable from sources in Germany and the United States.
There are several professional BMW motorcycle restorers at work in North America and Europe. Two American membership organizations, Vintage BMW Motorcycle Owners and the BMW Veteran Motorcycle Club of America are dedicated to the preservation of vintage BMW motorcycles.
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