News – Presentation of the motocross Yamaha YZ250F and YZ450F 2014 – Used YAMAHA

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Introducing the 2014 Yamaha YZ250F and YZ450F motocross

News - Presentation of the 2014 Yamaha YZ250F and YZ450F motocross - Used YAMAHA

The Yamaha 4-stroke motocross range underwent profound changes in 2014: the YZ250F notably adopted the principle of an "inverted" engine tilted backwards discovered on the YZ450F at the end of 2009, while the latter received improvements aimed at improve its usability.

The Yamaha 4-stroke motocross range underwent profound changes in 2014: the YZ250F notably adopted the principle of an "inverted" engine tilted backwards discovered on the YZ450F at the end of 2009, while the latter received improvements aimed at improve its usability.

Everything on the 2014 YZ250F

After a rather calm 2013 vintage in terms of technical developments (read our), Yamaha’s YZ 4-stroke range receives a serious boost: the Blues are aiming for the win and giving themselves the means..

The Iwata crest has in this regard put the package on the 250 cc, whose aging five-valve single-cylinder carburetor gives way to an engine technically similar to that discovered on the YZ450F 2010 (read our).

This block is distinguished by the inclination of the cylinder backwards, which allows the positioning of the intake and the exhaust to be reversed. The air-fuel mixture is thus introduced from the front – taking a more direct route than from the rear – and the burnt gases escape from the rear.. 

Although technically and visually identical to that of the "four and a half", the engine of the YZ250F 2014 differs in many aspects: the cylinder head, piston and cylinder are new and of course smaller, as are the valves. . Its gearbox is also unique and is coupled with a clutch announced more flexible.

As on the 450 cc, the exhaust adopts a specific configuration: the manifold goes right around the engine, which makes it possible in particular to shorten the silencer in order to improve mass centralization. An objective also pursued by "burying" the 7.5 liter tank as far as possible inside the frame..

The injection has improved significantly, while the use of a thinner and shorter radiator and a shorter rear loop, in particular, has made it possible to reduce the weight. In the same vein, Yamaha has reduced the dimensions of the oil pan and simplified the lubrication system..

In terms of the chassis, the YZ250F 2014 is also based on the YZ450F: both are built around a hydroformed bilateral beam frame made up of ten different types of parts. They both receive a Kayaba inverted fork with new springs as well as a redesigned shock absorber for more stability. The front wheel axle is bigger (22mm) and the rigidity of the handlebar mount is increased.

Finally, the line evolves thanks to new mudguards, a now prominent air intake and an overall refined silhouette for more aggressiveness. To increase the resistance of the decoration, Yamaha uses a method called "In Mod Graphics" which consists of inserting the film into the mold before the part is injected..

Everything on the 2014 YZ450F

For its part, the formidable YZ450F is content with lighter evolutions, but which are important: its 4-stroke single-cylinder with double camshaft would for example be both more efficient and easier to operate. To achieve this feat, the Blues have enlarged its valves and redesigned its intake and exhaust ducts as well as the profile of the cams..

In addition, the injection has been revised and now uses a new, more efficient control unit (ECU), while the new gearbox staging favors relaunching and acceleration in the first reports..

The clutch uses "optimized" compression springs and discs while new specifications have been retained for the shaft and primary and secondary drive gears. All for the benefit of more comfortable gear changes.

As on the YZ250F, the 450 cc offers different injection configurations to adapt to the terrain profile or the driving style via the Yamaha "Power Tuner" box. The similarities with the small "two and a half" continue at the chassis level, since the YZ450F uses the same components and the same frame – a little reinforced anyway! – than his little "sister".

Same thing on the aesthetic level, since the two motorcycles share the same stylistic evolutions and identical colors: in 2014, the YZ250F and YZ450F will be available in Racing Blue (blue and white) and Sports White (white and red) at non prices. press releases.

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