Sweet Motorcycle - The New Ducati S2R
File under Ducati New Products
Author: Ducati Press Release
Location: Normandy, France
Over the years, Ducati desired to produce a companion model to the classic Monster, with an even more aggressive sports design. Just one year after the launch of the most powerful and exclusive model in the Monster range – the S4R, built with numerous components of the Superbike motorcycles – Ducati now presents the S2R.
This is the birth of a new product range, which Ducati has named the "Monster SR" range, now featuring the Monster S4R, their flagship product, the ultimate expression of the naked bike, and the brand new Monster S2R, the essence of a sports bike combined with maximum enjoyment and functionality.
This family of naked bikes, at the cutting edge of style and technology, as well as the pinnacle of sporting performance, now boasts a number of exclusive and original features.
The Monster S2R, with its less aggressive engine design (when compared with the S4R), still shares all its big brother's extreme componentry, with everything required to ensure a gutsy, enjoyable and exciting ride. The new model is intended for riders who prefer the fluid, graduated, and less intimidating power of an 800 cc air-cooled two valve engine over the exuberant power of the hyper-sports water-cooled 4V engine of the S4R.
The 2005 model Monster S2R copies the overall style of the S4R, with the differences based on the new engine. The use of a twin-cylinder, 2-valve air-cooled engine, thus without liquid radiator, makes the latest in the Monster range even more sparse & streamlined. On the other hand, the new model features all the aesthetics of the SR series, including: single–sided swing arm, double vertically-configured exhaust pipes on the right side, and special colour schemes. The sports front fairing and coloured seat cover are not present, and the handlebar is of the conventional steel type rather than the aluminium variable cross-section version.
Chassis and running gear
The development of the chassis and running gear for the Monster SR family has resulted in two important changes: new and more eclectic aesthetics, but more importantly, increased ground clearance for cornering. The maximum theoretical angle in cornering (with both suspensions compressed by 2/3 of their stroke) is now 48°, for extreme use of the bike even on track.
The structural parts involved in achieving this result are the following:
- Single-sided swing arm in aluminium tubing
- exhaust system
- separate footpeg brackets
- aluminium side stand
- high riding position (shock absorber shaft 3mm longer, front forks mounted 10 mm higher)
The new Monster S2R uses a frame which is practically identical to that of the 800 i.e. version, except for a few details. It was not possible to use the frame of the S4R due to the different routing of the intake ducts. Indeed, on the Desmoquattro these units are practically straight and strongly angled relative to the plane of the head on the cylinder. On the 800 cc Desmodue and all other two-valve engines, on the other hand, the intake ducts are routed in a very different way. They are only slightly angled relative to the head/cylinder plane, so that the airbox also has a different shape in comparison to that used on the S4R.
The S2R's front fork is an upside-down 43 mm diameter Marzocchi unit, and the rear shock absorber is a Sachs unit with adjustable spring preload and rebound damping. This shock absorber features adjustable shaft length, thus enabling ride height adjustment. The two floating front brake disks are 300 mm diameter units. They are acted on by double-piston floating calipers. The rear brake has a single 245 mm disk with fixed double-piston caliper.
The fuel tank is constructed in techno-polymers by rotational molding. This enables the plastic material to be molded onto a shell composed of two parts which form the negative of the tank itself. This shell is spun on two axes in a special carousel to enable the liquid nylon polymer to cover it in its entirety. The process is run at a specific temperature at which the plastic polymerizes and thus hardens to form the walls of the tank.
The Monster S4R and S2R have many parts in common. The single-sided swing arm, which enables use of an exhaust system with two small silencers, one above the other and at a high lateral position, is the same. This important component of the rear suspension is lighter by 20% than the swing arm of the Monster 800, resulting in a weight reduction of 1100 gm, and has an aluminium trellis design. The main component of the swing arm is an extruded oval cross-section tube (for maximum rigidity) welded directly to the swingarm pivot casting. The footpeg brackets are also identical to those used on the S4R. They are positioned very narrowly to enable the rider to assume a more streamlined position (with both legs snug against the fuel tank). Furthermore, the passenger and rider footplates are separate. For specialist uses (on track, etc.) the rear footpegs can be removed. The front footpeg brackets are fixed to the engine casing with two bolts and to the swing-arm pivot via an elastic bushing.
The variable section Magura handlebar, the same as that used on the S4R, has a very special technical specification. It is constructed in aluminium, with a 22 mm diameter at the grips, widening out to 28 mm at the center for better rigidity. The intermediate sections taper smoothly between the two specified diameters. The handlebar tubing has a wall thickness of only 4 mm for exceptionally light weight.
Another highly prestigious component of the Monster S2R is the use of 5 spoke Marchesini rims with 5.5" rear rim to enable mounting wide rear tyres (180/55).
Desmodue 800 i.e. engine
The Desmodue 800 i.e. is certainly one of Ducati's most famous, highly appreciated and versatile engines. The piston stroke is 66 mm with a bore of 88 mm for a total displacement of 802.84 cm3. The connecting rods have a center distance of 124 mm, and are newly designed. To improve their fatigue strength, their surfaces are subjected to chemical vibration polishing. They are thus smoother and more even than a conventional connecting rod. This finishing reduces surface micro-defects which can promote cracking. The piston of the 800 cc Desmodue engine is cast, with a reduced compression height and is very light weight, is graphite-coated on the jacket and uses a new set of piston rings for significant blow-by reductions. The piston ring seats are anodized – surface hardened to prevent contact adhesion of the rings. The cylinder has two chamfers at its base to enable insertion of the gudgeon pin, which would otherwise be difficult due to the reduced compression height of the piston. The camshaft is mounted with ball bearings at both ends. The valve closure cams are designed to reduce acceleration of the valve head as it approaches its seat.
The engine is of course equipped with computer controlled electronic injection.
The lubrication system on the Desmodue 800 i.e., which also has a cooling radiator, is extremely rational and functional. For example, the duct carrying the oil to the left hand clutch housing (and which runs in the right hand housing), is machined into the casting itself. This means that there is no need for oil lines. The gearbox is a six speed unit, the selector forks and drum have been designed to optimize gear selection ease, and a more evolved version of the renowned APTC clutch is used.
The primary transmission sprocket features backlash recovery mounts for significantly reduced running noise. The toothed wheel forming the sprocket is thus composed of two superposed components, held under tension by a set of cylindrical coil springs. This reduces the inevitable backlash in primary transmission gear meshing. The gear ring mounting to the clutch casing includes cylindrical coil spring damper, to dampen peak torque delivery to the gearbox when the clutch is released and during powerful accelerations and decelerations.
This exclusive device provides a torque delivery which is a function of the torque applied to it. This makes it possible to considerably reduce the force required to operate the handlebar clutch lever, while ensuring transmission of engine torque to the gearbox primary shaft. Depending on the design of the APTC clutch components, the transmissible torque, for a given size of clutch disk, can be conveniently increased over that transmitted by a conventional clutch. Another important feature of the unit is its capacity to automatically limit the reverse torque ("slipper clutch") generated during aggressive deceleration. The APTC clutch was developed for the smallest Ducati two-cylinder engine, the Desmodue 620 i.e., and is now also used on the Desmodue 800 i.e.. In a conventional clutch, the maximum drive torque transmitted from the crankshaft to the primary gearbox shaft depends on the contact surface between each driven and driving clutch disk (and hence their average radius), on the friction coefficient of the disk material and the force with which the disk pack is driven together (which is a simple function of the cylindrical coil springs acting on the pressure plate). In the APTC clutch, on the other hand, the force compressing the disk pack is not dependent merely on the pressure plate springs, but is also due to the special design of the hub, in other words, the internal device driven by the driven disks and mounted to the primary gearbox shaft. In this way the pressure plate coil springs, which are bolted to the drum studs, need not supply the full load required to compress the clutch disk pack in order to transmit the engine torque.
This significantly reduces the hand force required to operate the handlebar lever compared to that required for a traditional clutch design. The design of the drum is the key to the secret of the APTC clutch. The drum actually generates part of the load on the disk pack as a function of the engine torque. This load thus makes it possible to transmit increasingly higher torques, up to the limit determined by the size specification of the device and the friction between the disks themselves. To sum up, the relation between the clutch input torque (applied torque) and the output torque (transmitted torque) is linear, while with a conventional clutch this ratio is fixed at its maximum, even when the actual applied torque is lower than the maximum transmissible value. This is due to the fact that the load exerted by the pressure plate springs is always constant. Applying the same logic, but in the opposite direction of torque transmission, the greater the reverse torque applied to the APTC clutch, the lower its transmission to the crankshaft.
The S2R's exhaust system, the layout of which is identical to that of the S4R, has two manifolds mounted inside a pre-silencer located behind the engine, under the swing arm pivot. This unit has two chambers divided by a cavity containing the catalytic converter.
The exhaust gas thus enters the first chamber, passes through the catalytic converter, and then enters the second chamber. From here, via two separate pipes, it is sent to the two three-chamber silencers which are mounted one above the other on the right hand side of the motorcycle.
Click here to go directly to the Ducati S2R page. (If my wife is reading this, can I have one.... please??)