2005 BMW K1200 S
By launching the K1200 S, BMW Motorrad has entered new territory - and there is good reason. For many years, BMW has been well represented in most market segments, including the entry-level single-cylinder F650 range, and the flat-twin and four-cylinder touring, sports touring, cruising, adventure sport, and roadster categories.
However, the high performance sports aspect of the market never saw a true representation from BMW. This presented an exciting challenge for Motorrad designers and engineers and also offered tremendous sales potential - especially in the UK with its high percentage of sports and super-sports bikes.
Several years ago, a logical decision was made to enter the sports segment of the market and create a machine that would serve as a prestigious and exciting top-end addition to the current model line-up. The aim was for this motorcycle to attain the same level of desirability and reputation that has always been enjoyed by BMW's M-division performance cars.
It was however never BMW Motorrad's intention to create a super-sports motorcycle designed and engineered for the racetrack rather than the road - or to produce a hyper-sport machine with the highest possible top speed. The latter is no longer an important selling point among riders. BMW Motorrad's intention has been to design a machine that complements and straddles both categories - and also attracts customers from the high performance sports touring sector of the market.
With the launch of the new K1200 S, BMW has introduced a motorcycle that is lighter and more agile than a hyper-sports machine - but just as fast - as dynamic on the track as a super-sports machine but far more usable in everyday riding situations.
Superiority in 'duolever' suspension design, with electronic suspension adjustability (ESA) options, should firmly establish the K1200 S as the most technologically advanced motorcycle available today.
Clear market positioning of the K1200 S attempts to persuade many riders who are tired of riding motorcycles that only perform at their best on a race circuit - or in a straight line - to realise that it is possible to have immense but usable horsepower, significant high speed capability, and unquestionable ergonomic efficiency without compromising BMW's legendary comfort levels and distance capability.
The narrow K1200 S inline engine outputs a massive 167 bhp and is no wider than that of many 600cc machines. It is tilted forward 55 degrees for an optimum low centre of gravity which also contributes to an 'ideal' weight distribution ratio of 50:50. Digital Motor Electronics and three-way catalytic emission management conform to the strictest environmental standards.
BMW expects the majority of K1200 S purchasers to be conquest sales from other manufacturers and will therefore make demonstrator machines available at every BMW Motorrad dealership. The UK market launch of the K1200 S is 25 September 2004 and the on-the-road price for this model is £9,750 for the standard version or £10,545 for the sports integral ABS version. This year's production will feature Indigo Blue Metallic/Alpine White, and Sun Yellow non-Metallic/White Aluminium Metallic/Dark Graphite Metallic colour schemes. Single colour variants will follow in early 2005.
Overall concept and model features.
The speculation has now come to an end. BMW's long-awaited new
model featuring a brand-new high-performance four-cylinder power unit and revolutionary suspension technology, is in dealer showrooms.
The new BMW K1200 S sports machine with an engine power output of 123 kW (167 bhp) and a dry weight of 226.5kg (248 wet, including fuel) offers the highest standard of dynamic performance.
By introducing the K1200 S, Europe's largest and most successful manufacturer of motorcycles has enlarged its model range and entered the sporting high-performance motorcycle class so far dominated by Japanese manufacturers. The K1200 S is a synthesis of high performance, precision, and safety.
Conceived as a sports machine from the start, the K1200 S is a singular and independent motorcycle within BMW's K family. It is radically new and innovative in every respect. The K1200 S has no predecessor in the current BMW Motorrad model range and follows no role model. On the contrary, the K1200 S is BMW's concept of a sports motorcycle - supreme riding precision and agility, high engine power output (specifically for road performance) and safe and superior handling in all practical situations.
The K1200 S does not compromise. Instead, it combines all the features previously regarded as largely incompatible. For example: sports performance and dynamism are combined with comfort, agility and ease of handling; supreme riding stability and high performance are coupled with everyday riding qualities; a slim-line sporting appearance is combined with efficient protection from wind and weather and superior rider ergonomics.
The K1200 S has all the virtues typical of BMW motorcycles but these have now ascended to a higher level. The new machine is fully suited to riding with a passenger and covering long distances; it offers a long service life and maintenance is minimal; it complies fully with environmental requirements (thanks to highly advanced emission management and a fully controlled three-way catalytic converter); and it offers active safety of the highest standard when braking (assured by the most advanced braking system on the market - BMW Motorrad Integral ABS).
The K1200 S is the only sports motorcycle to feature maintenance-free shaft drive. In conjunction with the Paralever swinging arm (developed to an even higher standard and reduced in weight) the drive shaft has been optimised to a higher standard than before - its higher level of unsprung mass is virtually imperceptible even when the rider adopts a sports style of riding. Featuring innovative technology, and a new standard of riding characteristics in the sports bike segment, the K1200 S redefines the criteria for its class. The K1200 S has opened up new customer potential for BMW Motorrad.
Unique concept for ideal riding dynamics and ergonomics
The first decision in the approximate five-year development period (from the initial idea through to production reality) was to carefully consider the overall concept regarding the drive-train, configuration and arrangement of the engine, and the overall package. It soon became clear that the advantages of a low centre of gravity, typical of all flat-twin and existing K-models, had to be retained on the new motorcycle. Research and fundamental examination of different engine concepts confirmed that (from the perspective of power, weight and space requirements) a four-cylinder power unit fitted crosswise was the optimum solution for high-performance motorcycles.
The only drawback with that configuration was a high centre of gravity. However, by tilting the cylinder bank forward to an extreme 55 degrees and fitting the engine at its lowest possible point, BMW's engineers overcame that particular disadvantage. In addition, the entire engine block is extremely narrow to ensure adequate clearance when leaning into bends - allowing exceptional lean angles. Together with the extra-low, V-shaped radiator, the configuration interacts with the wheel suspension and guidance units to allow ideal frame curvature above the cylinder head to keep the motorcycle slim and narrow. With the frame profiles running close together at the rear, the new K1200 S shape also enables the rider's knees to be tightly pressed against the machine.
The overall result of this re-thought package is optimum geometric configuration of riding dynamics and ergonomics. The perfect seating position is tailored for the rider and allows an active riding posture with clear vision of the front wheel. It also has an appropriate standard of comfort and relaxation. The result is that the K1200 S handles dynamically and safely in every situation, making riding on the road confident and stress-free.
Innovations on the running gear and electronics.
The BMW Duolever marks a quantum leap in technology in front-wheel suspension and makes a significant contribution to the motorcycle's excellent riding characteristics. By introducing this all-new, front-wheel suspension system BMW Motorrad has enhanced its leadership in suspension and running-gear technology and still ensured a sensitive response, at all times, with clear feedback from the front wheel. In conjunction with the four-cylinder concept, it also offers the advantage of compact dimensions.
BMW Motorrad is now introducing another world-first in motorcycle production with the ESA Electronic Suspension Adjustment which has advantages not previously seen. Based on CAN-bus technology, the advanced on-board network provides a wide range of different functions and reduces the procedures required for diagnostics by intelligently combining the motorcycle's electrical and electronic systems.
Highlights in technology at a glance
supreme performance ensured by a free-revving, high-output straight-four power unit with features carried over from Formula 1
cylinder bank of the four-cylinder, in-line engine tilted 55 degrees for an optimum centre of gravity
engine output 123 kW (167 bhp), maximum torque 130 Nm (96 lb-ft) at 8,250 rpm
Digital Motor Electronics and three-way catalytic emission management to the strictest environmental standards
supreme riding precision and maximum riding stability provided by extra-rigid aluminium suspension with Duolever wheel guidance at the front and Evo-Paralever wheel guidance at the rear
superior agility ensured by low, fully fuelled weight of 248 kg (547 lb) in road trim (DIN unladen weight including ABS)
supreme handling thanks to ideal running gear geometry, optimum mass distribution, and a balanced all-round concept
perfect balance ensured by a low centre of gravity
ergonomically enhanced seating position for relaxed, active riding
Electronically Adjustable Suspension (ESA) available as an option
Integral ABS (part-integral system) available as a deletable option for superior active safety
on-board network with electronic management; CAN-bus technology for enhanced functions combined with simple and straightforward wiring and low weight
electronic immobiliser as standard
maintenance-free, weight-optimised shaft drive
enhanced aerodynamics with good protection from wind and weather
wide range of features and accessories of the usual BMW standard dedicated to the K1.
Fitted crosswise, the straight-four power unit of the BMW K1200 S displaces 1157 cc. Maximum output is 123 kW (167 bhp) at 10,250 rpm; maximum torque of 130 Nm (96 lb-ft) is delivered at 8,250 rpm - with more than 70 per cent of the engine's maximum torque available from just 3,000 rpm. The engine power is easy to control at all times, which was BMW Motorrad's clear-cut objective when developing the new machine. Weighing just 81.3kg (179.3lb) including the clutch and gearbox, the engine is one of the lightest of its size in the market.
A well-conceived overall configuration, plus space-saving arrangement of auxiliary systems and the integrated gearbox enables a compact drivetrain with ideal concentration of masses in the middle of the motorcycle. The crankshaft of the K1200 S is just 430 millimetres or 16.93 inches wide, placing the engine of the K1200 S closer to current 600cc power units than engines in the 1000cc-plus segment.
A wide range of exceptional and innovative details and solutions - with design concepts carried over from the BMW's motorsport technology - added up to the creation of a unique drive system. And, as in Formula 1, it is not individual features and qualities but the perfect interaction of technical solutions and the optimum integration of the chassis and suspension. In this respect, BMW's engineers overcame the inherent disadvantage of the relatively high centre of gravity of a conventional four-cylinder engine by applying a solution of typical BMW ingenuity: the engineers intelligently built on a well-known principle, enhancing its design concept to an even higher standard by tilting the cylinder axis 55 degrees forward. This not only ensured a low centre of gravity but also provided the desired load on the front wheel - ideal for sports riding - giving a precise feel of the surface and clear feedback from the front end. The more acute angle also provided space for an aerodynamically-efficient intake system (directly above the engine) to ensure an ideal flow of power.
This second generation of four-cylinder engines, in more than 80 years of BMW Motorrad, again lives up to BMW's principle of offering unique solutions superior to the usual standard. It is fair to say that in concept and design, the engine of the K1200 S must currently be the most advanced and engineered power unit of its kind in the world of motorcycling.
Crank drive and engine block - slim and slender despite its 1200ccs
The crankshaft of the K1200 S power unit is forged from one piece of heat-treated steel. It comes with eight counterweights and the usual crank angle of 180° for consistent firing intervals. The stroke/bore ratio ensures adequate overlap of the bearing journals for superior stiffness. The crankshaft runs in anti-friction bearings with the main and conrod bearing journals measuring 38mm (1.50 inches) in diameter.
The principle of supplying oil to the crankshaft and bearings has been adopted from Formula 1. Instead of feeding lubricant conventionally in a radial flow via the crankcase to each main bearing and from there via a ring groove to the bores on the conrod bearings, lubricant for the bearings is fed directly into the crankshaft in an axial flow. From there the lubricant flows through holes in the crankshaft and onto the conrod bearings. This makes the usual ring groove superfluous and keeps the bearing slimmer and more compact (even though it carries the same load on the same width otherwise occupied by the groove).
The advantage is adequate freedom of design for a very short and compact crankshaft and a minimum distance between cylinders to keep the overall engine slender and compact. Another advantage of this oil supply concept is that the oil entering the crankshaft no longer acts against centrifugal forces but is supported by those forces. This allows the oil pump to run at a much lower pressure - pump characteristics and the supply volume being optimised for minimum power loss. Finally, oil supply to the main cylinders follows the usual pattern via the main oil pipes in the crankcase, to where oil supply bores lead to the bearings.
Two of the crankshaft counterweights serve as gears for the primary clutch drive and for driving the two balance shafts. The other counterweights are perfectly designed for smooth-flow dynamics - the ratio between mass and inertia radius being optimised.
The camshafts in the cylinder head are driven by a chain running on a sprocket bolted to the right end of the crankshaft. Running in anti-friction bearings, the connecting rods are lightweight forged components made from heat-treated steel. Measuring 120mm (4.72in) in length, they interact with the short stroke of the engine to enhance running smoothness. Together with the anti-friction bearings, the connecting rods weigh a mere 413 grams.
Again, taking a typical BMW concept, the upper conrod opening has a bearing bush for a running life of more than 100,000 kilometres or 60,000 miles. The connecting rods are split horizontally by proven crack-technology breaking through the large conrod opening specifically on the middle level by means of a tensile force applied suddenly and instantaneously in a hydraulic process. The fracture surface provided in this way subsequently allows extremely accurate assembly without any further centring of components.
The engine has lightweight box-type pistons featuring an extra-short piston skirt and three rings (two compression and one oil removal ring). Despite the high compression ratio, the piston base and valve pockets are flat in configuration thanks to the flat surface of the combustion chamber. This enhances the thermodynamically-efficient combustion process and allows weight-optimised contours on the bottom of the piston. Piston weight, complete with the pins and rings, is only 299 grams. To dissipate heat on the piston base surface subject to high thermal loads, the surfaces are cooled by oil-injection nozzles in the crankcase and therefore extend service life.
To eliminate second-order free mass forces inevitable on a straight-four power unit, the crankcase, operating via a tooth belt, drives two balance shafts positioned below the crankshaft. This ensures 100 per cent balance and force compensation - the balance shafts running in roller bearings spaced symmetrically in front of, and behind, the crankshaft to avoid additional mass momentum. The balance shafts run at twice the speed of the crankshaft. To minimise dissipation of sound waves and noise, the balance weights are connected via elastomer elements to the balance shafts.
Horizontally divided cylinder crankcase in open-deck design
The two-piece crankcase is made of high-strength aluminium alloy with the two sections split down the middle of the crankshaft. Die-cast, the compact upper section forms an extremely stable structure made up of the four cylinders and the upper bearing frame for the crankshaft. The cylinder block, complete with water jacket, is an open-deck design. The cylinder liners are finished with a wear-proof, low-friction nickel-silicon dispersion coating. The lower section, made as a pressure-casting, forms the counterpart for the main crankshaft bearing and serves as a mounting point for the gearbox.
Cylinder head and valve-drive based on Formula 1 design and construction principles
The output, performance features, quality of combustion and fuel economy of an engine depend to a large extent on the cylinder head and valve drive. In its design and construction, the four-valve cylinder head of the K1200 S is conceived to ensure optimum duct geometry, compact dimensions, optimum thermodynamics, and a reliable thermal balance. The single design feature absolutely crucial to optimum design and configuration of the cylinder head is the valve angle. A particularly tight or narrow valve angle, for example, will provide a straight intake duct and compact combustion chambers for high compression and optimum efficiency. The criteria crucial to valve drive and optimum output at smooth and unproblematic engine speeds (not affecting the valve drive) are stiffness, the minimisation of moving masses, and maximum overlap on the valves.
In choosing the configuration of the K1200 S power unit, BMW's engine specialists have opted in favour of follower arm timing with two overhead camshafts. This offers the perfect combination of maximum stiffness and minimum weight on the moving valve drive components, together with compact design of the cylinder head. Indeed, it is no coincidence that this principle has become the usual standard on today's Formula 1 power units. BMW Motorrad's engine specialists were therefore able to capitalise on all BMW's experience in motorsport in terms of lubrication and surface coating.
The valve angle on the K1200 S power unit is 10 degrees on the intake and 11 degrees on the outlet side - figures so far not produced by any other contemporary engines. Out of the two overhead camshafts, only the outlet camshaft is driven by a chain from the crankshaft, the intake camshaft being driven by gear drive from the outlet shaft. The big advantage is that this requires only one sprocket on the cylinder head, the entire concept thus provides an even greater precision in valve timing and keeps the width of the cylinder head to a minimum.
The camshafts are located directly above the valves. The overall layout of the cylinder head allows an ideal 1:1 transmission ratio on the follower arms,
thus keeping flexural tension to an absolute minimum and allowing the use of extremely delicate, lightweight levers. The speed limit chosen for practical purposes on production models is 11,000 rpm, while in mechanical terms the parts and components are able to take and withstand far higher speeds.
Valve diameter is 32mm (1.26in) on the intake and 27.5mm (1.08in) on the outlet side.
Record compression ratio
As already mentioned, the narrow valve angle keeps the combustion chambers compact with a flat upper surface. This is the prerequisite for a high level of geometric compression with a thermodynamically designed, largely flat piston floor. The compression ratio of 13:1 is unprecedented on a standard-production petrol engine, clearly confirming the ideal geometry of the combustion chambers with an ideal combustion process and optimum efficiency.
Oil supply identical to a race engine
The K1200 S comes with dry sump lubrication otherwise found mainly on race engines. The advantages of this principle are supreme dependability with a steady oil flow even under extreme conditions and the flat design of the crankcase, keeping the entire engine in a flat and low position and enabling a low centre of gravity. Not requiring an oil sump, the power unit is 60mm (2.4in) lower than with conventional construction. The oil reservoir is situated in the frame triangle behind the engine. The dual oil pump, driven by a chain from the clutch shaft, is housed in the rear crankcase area, drawing lubricant from the oil reservoir and feeding it under pressure initially to the oil filter (main flow filter) on the lower left side of the crankcase (within easy access from outside). From there, the pressurised oil flows into the main oil line in the crankcase and is spread out through internal holes leading to the lubrication points. The oil flowing back gathers at the lowest point in the crankcase in a recess within the bottom cap. The second pump delivers the oil flowing back, first to the oil cooler and then back to the oil tank through a patented re-flow system. The oil cooler is in the front fairing in a favourable flow position beneath the headlight. Finally, reflecting the overall philosophy of the machine, the oil cooler pipes are made of aluminium.
In an ingeniously simple process, the oil level is checked through a transparent, patented plastic tube outside the oil tank - used in service to drain oil from the tank with an overall volume of 4.2 litres or 0.92 Imp gals.
Engine cooling - keeping a cool head and good thermal balance
An intelligent cooling concept ensures a perfect thermal balance within
the engine. The flow of coolant between the cylinder head and the cylinders is subdivided 73:27 by appropriately dimensioned flow cross-sections. The coolant flows crosswise through the cylinder head with re-cooled coolant entering the cylinder head on the "hot" outlet side. This means that thorough cooling of the cylinder head ensures rapid dissipation of heat and an optimum temperature balance precisely where the thermal load is greatest.
The reduced flow of water on the cylinders enables the engine to warm up more quickly and reduces cold running wear and friction, also improving fuel economy.
The water pump is mounted on the left side of the cylinder head, where it is driven by the intake camshaft. This configuration and direct injection of cooling water into the cylinder head render the usual hoses superfluous and keeps the remaining hoses (leading to the radiator) extremely short. With the engine requiring only two litres of coolant, weight is once again reduced. The patented radiator also boasts motorsport technology: trapezoidal and appropriately curved in design, the radiator is fitted at the front lower end of the fairing - again for a lower centre of gravity. Thanks to the high degree of efficiency and aerodynamic optimisation of the fairing and flow conditions, a relatively small surface of only 920 sq cm ensures adequate dissipation of heat under all conditions. The integrated thermostat allows the engine to warm up quickly and the dirt trap fitted in front of the radiator has been optimised for perfect aerodynamics.
Alternator and starter
To keep the K1200 S slender and dynamic, the electrical ancillary units (as well as the drive systems) are fitted behind the crankshaft in the open space above the gearbox. The alternator is driven by the primary gear on the clutch and has a maximum output of 580 watts and maximum power of 42 amps. The layshaft starter is connected by a free wheel running on the alternator drive gear.
Power transmission - multiple-plate oil bath clutch and cassette-type gearbox
The K1200 S is also unique among production motorcycles in its gearbox technology: for the first time in the history of BMW shaft drive, the K1200 S features a multiple-plate oil-bath clutch (the diameter of the friction plates is 151mm/5.94in) and a gearbox fully-integrated with the angle drive in the engine housing. The big advantages of this configuration, of course, are compact dimensions and efficient concentration of mass weight.
By introducing this concept, BMW Motorrad has not taken the usual approach. Instead, the gearbox is a separate, built-in unit commonly referred to as a cassette gearbox. This concept comes from motorsport where it allows rapid and efficient replacement of parts. On a production machine it offers advantages in the assembly process because the gearbox can be pre-assembled as a single unit. With the gears shifted by claws, the two-shaft gearbox is slender and light. The natural process of shifting from one ratio to another is conducted by a gearshift cylinder, gearshift forks, and slide wheels to provide positive engagement. To save weight the hollow gearshift cylinder is made of a high-strength aluminium alloy running in roller bearings. The shift forks are also made of aluminium and are lubricated by oil, supplied under pressure. A particularly smooth gearshift is ensured by anti-friction bearing bushes featuring a smooth bronze/teflon surface coating for minimum friction.
To keep the gearbox short and compact, the two transmission shafts run above one another. The gears themselves are straight-toothed, which not only improves transmission efficiency - albeit by only a minor factor - but also helps to keep the gearbox slender and avoid extra width. Thanks to the compact structure of the transmission and the minimisation of noise from the gearbox housing, running noise is reduced to a suitably low level.
Drive shaft to the rear wheel - indispensable and unique in sports machines
Like all large BMW motorcycles, the K1200 S features a drive shaft to convey power to the rear wheel. With the engine fitted crosswise, the shaft drive configuration requires two pivot points - the pivot unit leading from the gearbox is fitted in the gearbox cover. The loss of efficiency resulting from such double-pivotal transmission is often overestimated because, in practice, it is only a few per cent. In comparison, studies confirm that because of a certain degree of wear and contamination, chain drive suffers a significant increase in friction. This reduces the degree of efficiency. Shaft drive operates without wear and maintains a consistent standard of efficiency throughout its full service life. The entire rear-wheel drive system is described in detail in the Suspension/Paralever chapter.
New engine management - now featuring individual cylinder management with anti-knock control
The K1200 S boasts the most advanced digital engine management currently available on a motorcycle. Indeed, BMW's BMS-K (BMW Engine Management with Anti-Knock Control) Digital Motor Electronics is an in-house development specifically for motorcycles. The new generation of BMS-K technology was featured for the first time on the R1200 GS and has now been upgraded for four-cylinder power units. Its most significant advantages are fully sequential, cylinder-specific fuel injection, integrated anti-knock control, rapid processing of comprehensive sensor signals by means of the most advanced micro-electronics, compact layout, low weight, and self-diagnosis. By introducing this sophisticated management system, BMW Motorrad is further enhancing the unique qualities already held for so many years in electronic engine management.
Momentum-based engine management with alpha-n control
Momentum-based engine management evaluates a whole range of parameters and delivers torque and drive power specifically geared to running requirements while finely adjusting the engine running conditions.
The alpha-n management principle - with indirect determination of air volume intake as a function of the throttle butterfly angle and engine speed - has been exported from BMW's existing models and enhanced to a higher degree. Engine speed and the throttle butterfly angle are as before and (by means of a potentiometer) remain the basic factors for determining the engine operation. Then, by assessing additional engine and ambient parameters (including engine temperature, air temperature, ambient air pressure) the engine management system, focusing on control maps and built-in corrective functions, tailors the volume of fuel injected and the ignition timing point to specific, real-time requirements. Fuel injection is fully sequential so that fuel is injected individually into the intake ducts, precisely geared to the intake stroke in the respective cylinder.
Variable pressure control for optimum fuel supply
Variable fuel pressure control in the supply system is another first-time achievement on a production motorcycle. The system does not have a re-flow pipe or function, but delivers only the amount of fuel consumed by the engine. In practice, this highly efficient control of fuel supply allows fuel pressure to be varied almost at random for optimum fuel/air mixture formation. Fuel supply is thus tailored to actual requirements by the electrical fuel pump, applying a principle unique on a production machine (and protected by patents). The fuel/air mixture is masterminded by an oxygen sensor fitted at the junction point of the four exhaust manifolds for precise determination of exhaust emissions and their composition. The result is greater riding pleasure combined with even better environmental compatibility ensured by exemplary emission management and low fuel consumption, and enhanced by precise riding and a sensitive response.
BMS-K also comprises the automatic idle speed and cold-start control functions. Idle speed is increased automatically whenever required in the warming-up process It is controlled by an idle speed stepper (bypass ducts for additional air) integrated into the airbox and by specific adjustment of fuel injection volume. Measuring 46mm (1.81in) in diameter, the throttle butterflies come with patented operation featuring progressive adjustment. The butterfly position is predetermined by the rider turning the throttle and is controlled with greater precision by a step motor optimising engine response and fuel amount.
Incorporating various functions as one, the entire system is lighter than ever before. The three-piece injection rail, made of plastic, incorporates the fuel pressure sensor and rod-shaped high-energy ignition coils housed in the cylinder head enhance efficiency of the new engine management system.
High compression and anti-knock control for superior fuel economy
Fuel consumption of the K1200 S is 4.7 litres/100km at 90 km/h and 5.5 litres/100 km at 120 km/h (60 and 51.4 mpg respectively). Considering the engine's power, performance and free-revving behaviour, this is truly outstanding in the supersports segment.
A major contributory factor to this superior efficiency is the unusually high geometric compression ratio of 13:1, a new record made possible only by anti-knock control. Following the R1200 GS, the K1200 S is the second BMW motorcycle to feature this protective function as standard. Two solid body sound sensors positioned between cylinders 1/2 and 3/4 detect any knock effects in the combustion process. The engine's electronic system responds by retarding the ignition and thus protecting the engine from possible damage. Conceived for unleaded premium-plus fuel (98 RON) under normal conditions, the engine, thanks to its efficient knock control, is able to run without the slightest problem and without manual intervention on premium (95 RON) or regular (91 RON) fuel. The only difference when using lower quality fuel is a slight decrease in maximum output and a slight increase in fuel consumption.
Intake system - large volume for optimum cylinder charge
With the engine tilted so far to the front there is space for an airbox right above the engine. The four intake manifolds lead directly into the intake system without any curvature that would reduce efficiency. With a volume of 10 litres, the airbox helps to boost the power of the engine and contributes to its high level of torque. Two funnels extending straight to the front for optimum flow conditions (a configuration made possible by the location) draw in the air required (from right and left of the headlight) in the ram pressure area on the fairing. Particularly at high speeds, this ram air effect helps to further increase the cylinder charge. The intake air then passes through two separate paper filters at the end of the funnels before going into the airbox. To facilitate service and maintenance, the filters are within easy reach after removal of the fairing side sections.
Apart from the modern cyclone oil separator (serving to purge air from the engine) the airbox also comprises the idle control system. It serves to hold the battery and is another example of well-conceived, functional integration to save both space and weight.
Exhaust system - with three-way catalytic converter and sporting sound
Four individual exhaust manifolds equal in length initially merge beneath the gearbox into two pipes and from there form a single pipe leading into the extra-large rear-end silencer (4-in-2-in-1 exhaust system). Round in shape, the silencer has a volume of 9.5 litres and operates according to the reflection principle. The outer skin of the silencer is protected thermally by the inner absorption layer, the metal-based catalyst incorporating 200 cells/inch² is fitted at the entry point of the manifolds leading into the silencer. The catalyst coating is a combination of rhodium and palladium, particularly resistant to high temperatures and with a long service life.
The entire silencer system made of stainless steel weighs a mere 10.4kg (22.9 lbs) making it the lightest exhaust system with a fully controlled catalytic converter in its market segment. One look at the way the manifold is fastened to the cylinder head shows the great attention to detail in the quest to save every gram. Finally, the sporting sound of the engine is ensured by careful sound engineering but still maintains legal sound emission standards under all circumstances and riding conditions.
Suspension that boasts the most advanced technology
The K1200 S has inspired BMW's suspension and running gear engineers to introduce a wide range of new ideas and concepts. For example, the rider can electronically adjust the springs and dampers at the touch of a button. Secondly, an important world-first is the front-wheel Duolever. In addition, the lightweight Paralever has been further enhanced for the rear-wheel suspension.
The frame, again for the first time, is of light alloy with inner high-pressure profiles visible from outside. The highly stable wheels are particularly light and stylish in design. Together with the rider's seating position, appropriate interplay of the suspension and the position of the engine ensures not only a low centre of gravity with the desired concentration of masses, but a well-balanced, ideal wheel-load distribution of 50:50.
High-precision, robot-built lightweight frame
The central load-bearing component on the K1200 S is the main frame which forms a bridge structure. The frame itself is a welded, composite configuration made of internal high-pressure moulded elements (IHU profiles). This forms the curved profile sections at the side and extrusion-pressed profiles together with die-castings that form the frame head and rear end with the swinging arm mounts.
The K1200 S is the first motorcycle with IHU-profiles. In BMW's in-house Aluminium Competence Centre at the Berlin plant, a high-precision robot welds the components together to form a common extra-rigid unit. With the engine tilted far to the front, the profiles on the main frame extend to the rear above the cylinder head. This means that shape is not dictated in any way by the width of the cylinder head. It also ensures ideal design and configuration of the frame which is kept appropriately slim and slender - an advantage also provided by the newly designed Paralever swinging arm, making it possible to locate the footrests lower.
Despite the low footrests, the rider of the K1200 S is able to lean over to an angle of more than 50 degrees in bends thanks to the overall configuration of the suspension and engine. The low frame structure, in conjunction with the new front-wheel suspension, also serves to provide smooth and favourable inflow of forces, thus minimising the loads acting on the frame. The mainframe weighs a mere 11.5kg (25.4 lbs). The engine is firmly bolted to the frame at six points and acts as a reinforcing element without assuming any load-bearing function. The lightweight rear frame is made of rectangular aluminium profiles welded to each another and bolted onto the mainframe at four points.
Reflecting the usual style and standard of sports machines, the K1200 S comes with only a side-stand when in standard trim. A main stand is available as special equipment and may be fitted easily and quickly on request.
A world-first following the great BMW tradition: the Duolever for perfect front-wheel suspension
The Duolever - BMW Motorrad's newly developed front-wheel suspension stands for supreme riding precision and directional accuracy combined with equally superior suspension comfort and clear feedback from the suspension elements. The result is an unparalleled feeling of riding safety in every situation, even when the rider prefers an ambitious, sporting approach.
The original idea came from Norman Hossack, and was then implemented and developed to perfection by BMW Motorrad. The front-wheel suspension is the most crucial component in giving a motorcycle ultimate riding precision and comfort. Recognising this essential criterion, BMW Motorrad has introduced all kinds of innovations on the front-wheel suspension. The first hydraulically dampened telescopic fork on a production motorcycle (1937); the longitudinal swinging arm ('50s and '60s); the long-stroke, high-comfort telescopic fork ('70s); and the Telelever (1993) were (and are) milestones in motorcycle technology invented or at least enhanced by BMW Motorrad and featured for the first time on BMW production machines. To this day the Telelever is the only front-wheel suspension system able to achieve genuine success next to the dominating telescopic fork. Indeed, the Telelever offers superior function and comfort features, and is the absolute optimum for the flat-twin machines in BMW's Boxer Series.
For the K1200 S, high-performance sports machine, the engineers at BMW Motorrad set out to find an even better solution with perfect kinematics. This was quite simply because the wheel elevation curve on all wheel guidance systems inevitably involves a certain compromise between the direction of spring response (comfort and fine response), anti-dive effect when applying the brakes (residual spring travel and feedback when braking), and the motorcycle's handling and riding stability.
The engineers found the right basic idea and philosophy in the Hossack fork developed by British inventor Norman Hossack back in the 1980s: front-wheel suspension with two longitudinal arms in parallelogram arrangement. Studies conducted by BMW Motorrad at the time of Hossack's invention showed that this configuration offers its advantages only in interaction with suitable wheel geometry. This meant that, for reasons of the package alone, it was not suitable for BMW Motorrad's motorcycle and engine concepts at that time. But when the original concept of the K1200 S started to take shape, the engineers took a closer look at Hossack's wheel guidance principle before developing and optimising its kinematics and ultimately reaching production standard.
Structure and kinematics of the Duolever
The kinematics of the new system - now named the "Duolever" - fulfils several contradictory requirements all in one: a rectangular pivot made of two almost parallel longitudinal arms turning within the frame holds the wheel bearing and allows the necessary lift motion. The wheel bearing, a light casting made of high-strength aluminium alloy, is connected to the longitudinal arms by two ball bearings and is therefore able to convey the steering forces and motion required. The straight line connecting the two ball joints forms the steering axis, an assembly similar to a pair of scissors. This serves to convey steering movements and disconnect the entire unit from wheel lift.
The handlebar is mounted conventionally on the head of the frame and may be turned in the usual way. A central spring strut pivoting on the lower longitudinal arm, finally, provides the suspension and damping effect required. The two longitudinal arms are suitably aligned to one another, allowing the wheel to adopt an almost ideal motion. Thanks to the kinematic configuration of the overall system, wheel elevation follows an almost straight line, with castor and wheelbase hardly changing regardless of spring travel. The wheel elevation curve is angled slightly to the rear, allowing the wheel to follow bumps and unevenness on the road in a natural process both when under pressure and in the rebound mode, thus evading undue forces and impacts from the surface.
In combination with the low-friction rotational movement of the longitudinal arms, spring response remains smooth and consistent even under high lateral forces, or when subject to severe bumps. The set-up of the suspension can be kept firm and taut without any noticeable reduction of comfort, thus maintaining the standard expected of a sports motorcycle.
With wheel forces being supported at a low point by the longitudinal arms (which keep the lever arm versus wheel contact point short and efficient), forces and momentum are fed into the frame in a smooth, favourable process reducing the load acting on the frame. The front-wheel suspension combines maximum stiffness with minimum weight because the shape and contours of the wheel mount can be chosen as required - thanks to the die-cast structure - thus being adjusted perfectly to force and momentum curves. The individual choice of wall thickness tailored to loads and forces helps reduce the weight of the entire structure without making any concessions in terms of strength and stiffness. Finally, following the main direction of force application, the longitudinal arms are subject to forces primarily in their own longitudinal direction. These are tensile and compression forces, meaning that through their configuration alone the arms are particularly stiff and sturdy.
Weighing only 13.7kg (30.2 lbs) the entire construction is about 10 per cent lighter than a comparable Telelever. The geometric configuration of the spring strut support allows a slightly progressive effect with an overall spring travel of 115mm/4.53in (60mm/2.36in inbound, 55mm/2.17in rebound). At 32 degrees right and left, the handlebar angle maintains the usual standards.
Through its kinematic configuration, the Duolever provides an anti-dive effect when braking - and the special point is that this effect remains largely consistent throughout the entire path of spring travel. Longitudinal forces acting on the front wheel when applying the brakes cause virtually no compression of the spring, only the dynamic distribution of wheel load resulting in a slight dive effect giving the rider the usual feedback on how hard the brakes are being applied - similar to conventional telescopic forks. Ultimately, therefore, the Duolever combines the feedback from the front wheel (so desirable to a sport rider) with the comfort and safety benefits of brake dive compensation.
Paralever swinging arm and lightweight driveshaft
Shaft drive is absolutely indispensable on a large BMW motorcycle and was therefore the obvious drive system for the K1200 S with its power unit fitted crosswise. Indeed, this not only reflects a BMW tradition but also (and in particular) offers well-known functional advantages: the truth is that a chain requiring careful service and maintenance is simply not appropriate on a top-end sports motorcycle for superior riding pleasure over long distances. The challenge in developing the K1200 S was to minimise the higher unsprung masses of a driveshaft and make sure the rider does not even feel the effect.
The ideal way to do this was with BMW Motorrad's new universal driveshaft unit complete with Paralever swinging arm (presented for the first time in early 2004 on the R1200 GS). Much stiffer and lighter than its predecessor, and slim and dynamic in appearance, this lightweight construction is a perfect complement for the concept of the new K1200 S. In design and construction it has been modified to meet the needs of the four-cylinder power unit and is appropriately strengthened for the extra power of the engine. The pivot angle at the output point from the gearbox has already been described in the Drivetrain chapter.
The main components of this new construction are the axle drive unit and the swinging arm. Made of a high-strength cast aluminium alloy, the Paralever swinging arm is particularly light, simply because in its design and dimensions it is tailored precisely to the load conditions and requirements encountered on the K1200 S. Although low in weight, the Paralever swinging arm is stiffer and stronger than conventional arms used on suspension. In geometric terms it is designed to provide 90 per cent dive compensation.
The pivot point of the swinging arm has been moved to a new position beneath the front universal joint on the driveshaft. This helps to keep the mounts suitably slender and ensures that the footrests are situated low down on the motorcycle. The pivot arm itself rests on a bearing in the stiff main frame, formed at this point by a highly stable cast light-alloy structure. The support point for the rear-wheel drive housing lies above the swinging arm, providing the possibility to fit the brake calliper at the bottom. The advantages are better thermal balance and easier removal of the wheel.
The swivel point for the axle drive housing in the swinging arm is below the axis of the driveshaft; the entire system of six pivot points being designed kinematically to avoid any effective changes in length on the drivetrain throughout the entire range of spring travel. The advantage in this case is that there is no need for any additional compensation for length and tolerance.
The spring strut pivots via a lever assembly, with about 30 per cent progressive action, near the swinging pivot point and is supported by a boom on the mainframe. The progressive action provided in this way gives the suspension a sensitive response combined with enhanced traction and sufficient reserves for riding with a passenger. In its basic design and configuration, the final drive housing has been carried over from the R1200 GS. At the same time it is closely aligned to the inner contours of the angle drive unit, thus avoiding any empty spaces or free areas inside. Precisely calculated, the crown wheel is very light in the interests of minimum weight and optimum smoothness, and the wheel flange is made of aluminium (again for reasons of low weight). Through its large diameter, the wheel flange gives the wheel perfect support, again helping to save weight around the hub of the rear wheel.
The visual highlight of this compact and elegant lightweight construction is the 50mm bore of the axle tube in the axle drive housing. Through its large surface and flow effects, it enhances the dissipation of heat from the final drive. With the entire axle drive unit being filled with oil for life, there is no further need for an oil change.
As on the R1200 GS, the driveshaft is made of two concentric tubes with a piece of elastomer in between to provide a reverse damping effect. The shaft itself runs without oil in the swinging column.
First-ever motorcycle suspension with electronic management - adjustment of suspension at the touch of a button, even when riding
The suspension system features high-quality, gas-pressure spring struts front and rear. Spring travel is 115mm (4.53in) at the front and 135mm (5.31in) at the rear. In its standard configuration, the rear sprung strut allows infinite adjustment of the inbound stroke for optimum damping and infinite adjustment of the spring base by 10mm (0.39in) enabling the rider, simply by turning a wheel, to set the suspension to different loads.
As an option, the rider is able to conveniently adjust the suspension and damping simply by pressing a button on the handlebar. Referred to as ESA or Electronic Suspension Adjustment, this system provides the option to adjust the suspension set-up with maximum comfort even when riding. Indeed, this is the first electronic suspension adjustment system on a motorcycle that adjusts the spring base as well as the damper inbound and rebound strokes on the rear wheel - and the inbound damping effect on the front wheel.
To make operation of the system as simple as possible, and to avoid the risk of incorrect adjustment, all the rider has to do is enter the motorcycle's current load condition ("solo", "solo with luggage", and "rider with passenger and luggage") and the system will adjust the spring base electrically by itself.
Depending on style of riding, the rider also has the choice of Comfort, Normal or Sports mode. Taking this input, the electronic control unit then chooses the appropriate damper rates based on optimum parameters - pre-set in the motorcycle's Central Electronic System (CES).
In all, this provides a choice of nine different variants, with the rider being able to change the damper setting while riding simply by pressing a button. For reasons of function and safety, the spring base can be reset only when the motorcycle is at a standstill. An electric motor complete with its own transmission serves to vary the spring base as required, while the damper rate is modified by small step motors on the damper.
Wheels and tyres - strong but lightweight wheels
The cast, light-alloy wheels were specially designed as brand-new highlights on the K1200 S. Light but at the same time very stable, the wheels come with special spokes designed with the help of a new, biontic calculation model taking the wide range of load requirements into account. The big advantage of such biontic calculation models is that they make allowance for structural principles and concepts of the same kind as nature: proceeding from load data and tightening parameters at the fastening points, such models calculate the optimum shape and design of a component in an iterative, step-by-step process.
The aesthetic benefit is that the front and rear wheels look light and dynamic. Despite these similar looks, the wheels are quite different in structure and layout. On the front wheel, the brake discs rest directly on a stable wheel spider without any carrier elements in between. The five radial arms of the spider extending from the hub and split, like forks, to support the rim via 10 cast spokes. With the forks being split tangentially and the spokes following a radial configuration, the front wheel offers excellent radial stability even under high wheel loads. A further advantage of this configuration is that it effectively resists the main load caused by high circumferential forces when applying the brakes.
This special design of the wheel, tailored to load conditions, helps to keep the spokes particularly slender and delicate, not only reducing the weight of the wheel but also giving the entire wheel structure a light and almost "transparent" look. On the rear wheel, the rim is also supported by 10-spoke arms in similar orientation. The difference is that in this case the spokes do not fork out, but rather extend all the way to the wheel hub. The brake disc is bolted onto the wheel flange. Dirty fingers and inconvenient hassle in checking tyre pressure are now a thing of the past because the tyre valve is integrated into one of the spokes at the side, ensuring convenient access in nearly every position of the wheel.
Wheel dimensions are 3.5in x 17 at the front, and 6in x 17 at the rear, running on tyres measuring 120/70-ZR17 and, respectively, 190/50-ZR17.
Brakes - high-performance EVO brake system and integral ABS (deletable) featured as standard
The K1200 S comes with BMW Motorrad's widely-lauded EVO brake system already featured in other flat-twin and K-Series models. The brake hoses are steel-clad for extra strength and safety, brake disc diameters of 320mm/12.60in at the front and 265mm/10.43in at the rear ensure maximum stopping power even at very high speeds and with heavy loads. In numerous tests this sophisticated system has proven its further benefits such as faster build-up of brake pressure than any other system. Brake operating forces are also kept to a minimum.
Ultimately, BMW's EVO brake system (EVO stands for Evolution) is one of the safest and most effective brake systems on any motorcycle. On the K1200 S this sophisticated brake system is standard, while BMW Integral ABS system is optionally available as the partly integrated sporting version. "Partly integrated" means that both brakes (front and rear) are activated whenever the rider pulls the brake lever, while the foot brake lever acts only on the rear-wheel brake. Integral ABS has been modified to match the sporting configuration of the K1200 S, and its control functions have been enhanced to a standard even higher than before. With the sports rider requiring a brake system that allows good feel and variable application of the brakes, the K1200 S precisely meets that requirement - virtually eliminating the risk of the motorcycle dropping over even when braking all-out. This advantage is ensured by the low centre of gravity and the particular geometry of the suspension interacting with the kinematic configuration of the Duolever. As a result, the ABS control system is able to capitalise on maximum tyre grip and friction, even when the rider applies the brakes to their maximum, guaranteeing supreme safety even during the most extreme braking manoeuvres.
Customers looking for a motorcycle without ABS are able to order a K1200 S without the ABS braking system (as an option) with an appropriate reduction in price.
Electrics and electronics
BMW Motorrad Single-Wire-System (SWS) - simply perfect for sensible functions of the on-board network
When introducing the R1200 GS early in 2004, BMW Motorrad presented its Single-Wire-System, a highly advanced, all-new system networking electrical and electronic components on the motorcycle. Combining sophisticated electronics with CAN-bus technology (Controller Area Network) this innovative on-board network offers a much wider range of functions than other conventional on-board networks, at the same time significantly reducing the number and intricacy of cables required.
With the SWS network, information is conveyed through one single wire (hence the name). And to ensure absolute security in a fully redundant system, the configuration comes with two wires for appropriate back-up.
The most significant benefits of this intelligent combination of electrics and electronics are the reduction of weight on both the wiring harness and the components used, a high level of robustness, and comprehensive diagnostic abilities. A further advantage is the easy integration of electronic accessories into the network, simple updates serving to flexibly extend and enhance the system whenever required.
The basic principle is to integrate all control units through one single wire to provide a common network transmitting all signals regardless of their subsequent function. The network comprises all information at all times, for all the components integrated into the system. The signals are then allocated to the right address at specific junction points, going straight from there to the appropriate electronic control units responsible for specific power-consuming items. There the information is processed and the appropriate functions are activated. This eliminates the elaborate and complicated process of wiring each individual function through a separate line, which also reduces the potential sources of error inevitable in a conventional on-board network due to the large number of lines and connectors. And this, obviously, is crucial to a high standard of all-round reliability.
Communication network and central diagnosis
With all control units forming one common communication system, the exchange of data is simple and efficient. Diagnosis of the overall system is equally simple and comprehensive and can be performed at one central point - the electronic "brain" filtering out insignificant data and interference signals within defined tolerance limits. This makes the system largely immune to interference such as electromagnetic noise. Including the anti-theft warning system and ABS, a total of five control units communicate with one another in the new K1200 S.
The instrument cluster also performs the functions of a control unit, and the BMS-K digital engine electronic control unit is responsible not only for engine management (as previously described) but also for the transmission of data to the diagnostic system. The Central Electronic System (CES), finally, masterminds the non-engine-specific electrical functions.
On-board network without conventional fuses
The entire on-board network operates without any conventional, melt-down fuses; the CES reliably switching off the function involved in the event of a short-circuit or malfunction. It then saves information on defects registered for centralised diagnosis, ensuring that each defect can be located quickly and directly. The big advantage of this electronic control function is that CES automatically re-activates the appropriate function each time the motorcycle is re-started, thus checking whether the defect is still there. Possible failure of a signal path will not affect the other functions, keeping the entire system reliable and failure-proof. The control units also serve as relays, only the starter being activated by a conventional relay.
A compact alternator developing 580 watts at 42 amps supplies the electrical system on the K1200 S. The maintenance-free battery has a capacity of 14 ampere/hours.
Electronic immobiliser - anti-theft security of the highest standard
The K1200 S comes as standard with an electronic immobiliser. Controlled via a transponder in the key to the ignition, this sophisticated system offers anti-theft security of the highest standard, equal to the security of a BMW car.
As soon as the rider inserts the key in the ignition lock and switches on the ignition, a chip in the key communicates with the Digital Motor Electronics via the ring aerial integrated in the ignition lock. Incorporating the electronic immobiliser algorithms, DME then initiates a challenge response process (the engine control unit activates a random "challenge" and the ring aerial/key replies with an appropriate "response" in order to identify themselves) and triggers an exchange of data between the coded chip and the electronic immobiliser. The data exchanged changes each time the engine is to be started. Whenever the response from the ring aerial fits the challenge presented, the engine control unit will release the ignition and fuel injection and the rider can start the engine. This technology is currently the best and most secure immobiliser technology available.
New instrument cluster in digital technology
The new on-board electronic system of the K1200 S allows the introduction of a highly advanced, fully-digitised, extra-light instrument cluster comprising the speedometer, rev counter and an information display referred to as the Info-Flatscreen. The Info-Flatscreen provides information on coolant temperature, the level of fuel in the tank, the time, and the gear currently engaged. If the motorcycle is fitted additionally with ESA Electronic Suspension Adjustment, the Info-Flatscreen provides additional information on the current suspension set-up. The overall mileage of the motorcycle, trip mileage, and the remaining mileage available from fuel left in the tank are also available on request by the rider. Any deficiencies in the system are shown by appropriate signals on the display. The entire instrument cluster is masterminded by a photoelectric cell and automatically illuminated at dusk.
All the motorcycle's switches and manual controls are of the latest generation introduced for the first time on the R1200 GS. The particular fortes of these switches and controls are a high level of function, clear design, and easy accessibility. The basic arrangement of switches and BMW's logic in operating the direction indicators has been maintained.
Body and Design
In its overall design, the K1200 S combines power with elegance, sportiness with perfection. Clear emphasis of the motorcycle's transparency and "lightness" is provided by visible technological highlights on the frame, the wheel mounts, and the wheels themselves.
The design of the K1200 S is absolutely unmistakable, entering new territory without any role models. Clearly, it is a motorcycle without a predecessor in the BMW range. It is brand-new in every respect. Yet in the harmony of its lines and in its expressive style, this new machine is clearly recognisable as a BMW and a member of the K-family. Virtually every visible component on the new motorcycle is also an element and product of design, particularly the fairing, headlight, fuel tank (with its cover on top), and the rear end complete with seat are crucial to the overall design concept.
The range of colours clearly underlines the unmistakable character of BMW's new high-performance motorcycle: Sporting Indigo Blue Metallic and elegant Granite Grey Metallic. The two, single-colour paintwork schemes, give the K1200 S a very sophisticated look. But there is also a choice of two multi-colour schemes of top quality: elegant Indigo Blue Metallic/Alpine White gives particular emphasis to the lines of the body, while the extrovert combination of Sun-Yellow Non-Metallic/White Aluminium Metallic/Dark Graphite Metallic is a particular eye-catcher. On the non-metallic colours, the frame and suspension components come in silver. On the multi-colour schemes they are finished in black.
Slender fairing in modular design for excellent aerodynamics
The K1200 S owes its sporting and slender silhouette to the equally slender, virtually narrow engine. This helps to keep the entire fairing slim and compact, while from the side, the elegance and smoothness of the surfaces is not marred by the usual air outlets. Instead, discharge air from the radiator flows within the fairing through an opening at the bottom of the engine spoiler to the outside. The spoiler itself is finished in black, giving the entire motorcycle an even slimmer, more athletic appearance from the side. The frontal view emphasises the dynamic appearance of the machine through the V-shaped transition of the upper fairing into the screen. This striking V-design with its clear subdivision of surfaces continues within the headlight lens and the front mudguard, giving the K1200 S its truly unique "face". Reflecting typical BMW style, the direction indicators are integrated in the rear-view mirrors, which offer unusually good visibility over a broad vista.
On the road the fairing of the K1200 S proves its aerodynamic qualities as the result of comprehensive tests in the wind tunnel. The objective in developing the fairing was to offer best-in-class protection from wind and weather, the emphasis once again on relaxed, enjoyable motorcycling and not on the achievement of merely theoretical records (such as air resistance reduced to a minimum). The flow of air on the fairing is guided by the side contours and the convex "blade" shape around the edges of the windshield to minimise wind pressure on the upper body of the rider and divert rainwater past the rider's shoulders.
Gill-shaped openings at the edge of the fairing around the sides use differences in air pressure to guide rainwater past the rider's feet. A carefully designed additional splashguard keeps contamination around the sides and at the rear to a minimum. At the front, the shape of the front-wheel mudguard supports the flow of air to the radiator, airflow to the oil cooler and the radiator itself being optimised to such an extent that the K1200 S, despite its superior power and performance, requires only relatively small cooling surfaces. Thanks to the modular structure of the fairing, partial removal of fairing elements for servicing is simple and straightforward. The front end, which is made of two plastic shells, is a self-supporting unit and offers a wide range of support and fastening functions in holding cables and fairing components. The headlight is a load-bearing element on the front end, again helping to keep the entire structure light and easy to assemble.
Headlight in clear-glass look and free-form surface technology - striking in design, safe on the road
Striking in its design, the headlight of the K1200 S houses no less than three units (one low-beam, two high-beam) with H7 bulbs. The headlight cover finished in clear-glass look is made of impact-proof extra-light polycarbonate. The reflectors in free-form surface technology are tailored precisely to geometry light requirements, ensuring an excellent light distribution and illumination of the road ahead. To facilitate replacement of the bulbs, the headlight is easily accessible from the rear.
Fuel tank and seat - specially designed for perfect rider ergonomics
The fuel tank on the K1200 S is made of light, impact-resistant plastic and has a capacity of 19 litres (4.2 Imp gals) including 4 litres reserve. The tank is fitted almost in the middle of the motorcycle, behind the airbox, helping to provide a perfect centre of gravity. The overall package of the motorcycle serves to keep the tank slim and slender around the rider's knees, allowing optimum knee grip. The shape and design of the tank follows functional requirements and the space available, its compact structure providing maximum capacity with minimum material. Production of the tank in a rotation process allows maximum freedom in the external design of the tank and its structure. This freedom BMW's designers have used to give the tank fairing a clear contour with interchanging light and shadow effects for a different look from every perspective.
The seat also follows this interesting design language continuing into the panels at the rear. In designing the double seat, the designers and ergonomics specialists focused on a criterion called "step arch length" (1,810mm or 71.26in). This specific measurement covers the total distance between the rider's two, foot contact points on the ground measured over the inner length of the legs, taking not only the rider's height into account but also the shape and width of the rider's seat. While the seat itself is not adjustable, its distinctive waistline around the tank ensures very good access to the ground and at the same time keeps the rider's knee angle very comfortable. A further advantage is that this configuration offers the rider significant freedom of movement even with a sporting style of riding.
The height of the standard seat is 820mm (32.38in). A seat which is lower at the rider's seating area (with a step-arch length of 1,780 mm (70.08in) and a geometric seat height of 790mm (31.1in) is available as a no-cost option for the shorter rider. It may even be fitted subsequently as special equipment at extra cost.
Although the seat is sporting and slender in design, the seating areas for the rider and passenger have been carefully designed to provide sufficiently wide seat surfaces with adequate support. The final result, therefore, is a standard of seating comfort superior in the sports motorcycle market, particularly for the passenger. Despite its sporting character, the K1200 S is just as suitable as every other BMW for riding long distances, going on an adventurous tour, or taking a passenger in genuine style. Indeed, straps for fastening luggage integrated beneath the seat make the K1200 S even more suitable for a lengthy journey.
Range of equipment,/p>
Options and special equipment - cases variable in capacity and customisation
It is a well-known fact that the most attractive motorcycle tours are not right outside your front door. This is no problem with the K1200 S, which is ideally suited to long distances and tours thanks to superior ergonomics. But if luggage is required, then conventional cases are hardly appropriate for a sports motorcycle. This is precisely why BMW Motorrad offers dedicated cases for the K1200 S - BMW sports cases combining function and sports design all in one. This newly developed luggage system with its perfect match of textile and solid plastic materials can be fitted and removed from the motorcycle within a matter of seconds thanks to clamps on the machine hidden almost completely out of sight. Variable in capacity, the cases can be enlarged from 17 litres in normal configuration to 25 litres on each side when expanded. The waterproof inner bags are fully integrated.
BMW Motorrad's usual wide range of options and special equipment provides maximum freedom in customising the K1200 S to an even higher standard. The options come straight from the factory in Berlin. Special equipment is fitted by the customer's BMW motorcycle dealership, as are any subsequent special options.
lower rider's seat (approx 790mm/31.1in, step-arch length 1,780mm/70.08in)
deletable BMW Motorrad Integral ABS option
ESA (Electronic Suspension Adjustment)
lower seat (approx 790mm/31.1in, step-arch length 1780mm/70.08in)
preparation for BMW Motorrad Navigator II
BMW Motorrad Navigator II
waterproof tank bag
set of sports cases, including case supports
anti-theft warning system.
Panniers (each) - £165
Tank bag - £150
Tank pouch - £95
Centre stand - £135
Anti theft alarm - £145
* Prices current as of 1 November 2004
Engine Capacity - 1,157 cc
Bore/stroke (mm) - 79/59
Output - (kW/bhp) - 123/167 @ 10,250 rpm
Torque - (Nm/lb-ft) - 130/96 @ 8,250 rpm
Configuration - In-line
No of cylinders - 4
Compression ratio/fuel grade - 13:1 / premium plus (98 octane) Valves/charge management - DOHC (double overhead camshaft) Valves per cylinder - 4
Intake/outlet dia - (Mm) - 32/27.5
Fuel supply - BMSK
Alternator (W) - 580
Battery (V/Ah) - 12/14 maintenance-free
Headlights (W) - Low beam 1x H 7/55 W, High beam 2x H 7/55 W
Starter (kW) - 0.7
Clutch - Multi-plate oil bath clutch, dia 151 mm Gearbox - Claw-shifted six-speed gearbox
Primary transmission - 1.559
Gear ratios - I - 2.521, II - 1.842, III - 1.455, IV - 1.287, V - 1.143, VI - 1.015
Rear wheel drive - Driveshaft
Final drive ratio - 2.82
Frame - Composite aluminium frame with IHU/extrusion-pressed profiles and die sections
Front wheel suspension - BMW Duolever
Rear wheel suspension - BMW Paralever
Spring travel front/rear (mm) - 115/135
Camber (mm) - 112
Wheelbase (mm) - 1,571
Handlebar centrepoint angle - 60.6°
Brakes - front, Double-disc brake, dia 320 mm, rear - Single-disc brake, dia 265 mm. BMW Motorrad Sports Integral ABS fitted as standard
Wheels - Light-alloy
front - 3.50 x 17 MTH 2
rear - 600 x 17 MTH 2
Tyres - front, 120/70 ZR 17, rear - 190/50 ZR 17
Length, overall (mm) - 2,282
Width, overall, with mirrors (mm) - 905
Handlebar width, w/o mirrors (mm) - 786
Seat height (mm) - 820 (790)
Weight, unladen, with full tank (kg) - 248
Max permissible weight (kg) - 450
Fuel tank (ltr) - 19
Acceleration - 0-100 km/h, 2.8 sec
Top speed - km/h(mph) - 200 (125) plus