Tuesday, October 07, 2008

Aprilia MXV 450



In a new ‘challenge within a challenge’, Aprilia is betting on the most revolutionary engine design of recent times in the tough, competitive world of motocross. The latest standard bearer for Aprilia’s off-road design concept is the MXV 450. With its incredibly compact V twin engine and amazing performance, the Aprilia MXV 450 is the definitive crosser for riders determined to win. As you can see from its essential and unmistakable styling, the MXV 450 is born to win. Its decisive, clear-cut lines tell you at a glance that you can expect light weight and fantastic build quality. Aprilia’s designers have made full use of the style emblems that define all Aprilia motorcycles to launch a brand new look in motocross motorcycles.


The extraordinary 45.2 engine has already accumulated titles and victories in enduro and supermotard racing. Now the same engine has become the heart of the new MXV 450, the first motocross bike in the world to be powered by a twin cylinder engine. In this dedicated motocross version, the 45.2 engine maintains the unique configuration that has distinguished it from the start. The V angle remains 77°, and the cylinders with wet liners remain integrated in the crankcase. The extremely rational arrangement of the engine’s accessories has made the Aprilia V2 engine one of the most compact V twins in the world, smaller than many singles of similar displacement. The engine’s amazing light weight is the result of radical choices in materials. The valves are in titanium, the crankcase in aluminium silicon alloy, and all covers are in magnesium. In fact, everything about the engine is designed for minimum weight in conjunction with maximum strength and reliability. All design solutions on the uncompromising MXV 450 have been dictated by the need to achieve the highest possible level of performance while extending the bike’s range of use. The under-seat exhaust, for example, features a new path for better motocross performance with more torque at lower revs. Valve gear based on a single overhead cam and four titanium valves per cylinder gives the best possible compromise between compactness, light weight and performance. Thanks to its advanced technology the 45.2 engine is extremely civilised and silent running even in this motocross version, and complies easily with FIM rules for noise emissions (94 dB threshold). The MXV 450 affords beautifully easy access for maintenance (plugs, oil filter, air filter), and boasts extended maintenance intervals, far above the average. The engine has a dry sump lubrication system with the oil tank integrated inside the crankcase to eliminate unnecessary oil pipes and reduce weight even further. The starter motor has been eliminated for the same reason. Starting is by kick-start only in order to minimise weight. The sophisticated electronic engine management system also introduces a number of motocross firsts. The Dell’Orto fuel injection system with 38 mm throttle bodies is managed by a programmable ECU that lets you switch between two different mappings at the touch of a button on the handlebars. The "full power" mapping is for use in conditions of good grip while the "soft" mapping delivers smoother power for use on more difficult surfaces. One click is all that it takes to obtain exactly the performance level you need. The salient specifications of the 45.2 engine on the new MXV: - electronic fuel injection; - dry sump lubrication with the oil tank integrated inside the crankcase. Separate lubrication for gearbox and engine ensures that the engine oil is not contaminated by clutch plate particles, and remains fully efficient for far longer; - single overhead cam, titanium valves; - single-piece crankshaft; - cylinders integrated in crankcase, wet liners; - “Hard/soft” mappings selectable from the handlebars; - electronic stepper motor idling control; - maximum engine speed 12,500 rpm;


The dimensions of the perimeter frame have been optimised for motocross use, and the entire frame has been developed to complement the engine. Its design is unique among motocross frames. A tubular steel trellis is interference fitted to pressed aluminium side plates to form a single structure. The engine also forms an integral part of the chassis, acting as a load-bearing element and contributing to exceptional overall rigidity.
Particular care has been taken over weight distribution. Weight has been centralised as far as possible to improve agility under all conditions. Weight reduction (one of the most important aspects of any motocross bike) was central to the design of every part of the MXV, from disc brake to frame. The swingarm is new, lighter and more elastic than before thanks to hydroformed members. The rising rate linkage system is damped by a fully adjustable Sachs racing monoshock with two damping settings for high and low speed riding. The Marzocchi upside down fork has 50 mm stanchions and is also calibrated for motocross. The fork is fully adjustable, so that you can set up your own suspension action exactly as you want it. The fuel tank has been redesigned to keep the bike’s centre of gravity as near as possible to the physical centre of the machine. Attention has also been given to eliminating protruding parts to reduce width and improve ergonomics. The centralisation of weight has led to a complete redesign of the filter box. The filter itself has been moved to the front of the bike to leave more space for the fuel tank which now extends back over the rear shock absorber. The new filter box also holds the throttle bodies and facilitates filter changing. The ECU and all the components of the electrical system are also housed securely inside the filter box. The exhaust system is new, with an under-seat silencer with twin tail pipes made entirely from titanium (collector pipes and silencer) especially for the BigBang engine. The minimal, batteryless electrical system is new too, and fully integrated inside the filter box. Engine and electrical system therefore form a single block. The two-tone stepped seat helps the rider hold his position at all times.


The unrivalled technology and performance of the chassis are supported by a fantastic braking system. The MXV is equipped with Nissin floating calipers and super-lightweight wavy discs (270 mm at the front), for unrivalled braking control in even the most challenging conditions.
A 240 mm rear disc with single piston Nissin caliper provides the perfect balance between stopping power and ease of control.