News – Motocross news 2015: the Yamaha 2 and 4-stroke evolve – Used YAMAHA

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New motocross 2015: the Yamaha 2 and 4-stroke evolve

News - Motocross news 2015: the Yamaha 2 and 4-stroke evolve - Used YAMAHA

By discovering the changes made to the Yamaha range of motocross bikes 2015, the evolutions of the 2-stroke YZ show how much the tuning fork brand is attached to this type of engine. The formidable YZF 4-stroke are also evolving. Details review…

By discovering the changes made to the Yamaha range of motocross bikes 2015, the evolutions of the 2-stroke YZ show how much the tuning fork brand is attached to this type of engine. The formidable YZF 4-stroke are also evolving. Details review…

YZ 85, YZ 125 and YZ 250: what changes in 2015

If Honda, Kawasaki and Suzuki have gradually – but surely – abandoned the 2-stroke on their motocross, this is not the case at Yamaha for whom the "cylinders with holes" still retain serious advantages (weight and maintenance costs). lower, in particular).

Based on this principle, the Iwata crest has dusted off its 2015 YZs, for example by offering them new lines very inspired by the … 4-stroke range. Front fender, radiator vents, side covers and seat cover give the 2015 YZ85, YZ125 and YZ250 a more aggressive and modern look..

Another modification common to the three motorcycles: a clutch free-standing adjustment knob is installed on the left lever. A very practical off-road equipment to measure the skating of the discs "on its own".

Mechanically, however, only the engine of the small 85cc receives changes: the timing of the intake and exhaust diagrams are changed to improve the responsiveness of this water-cooled block powered by a 28 mm carburetor.. 

On the 125cc and 250cc, the changes are mainly focused on the cycle part thanks in particular to the adoption of the inverted 48 mm fork (air / oil) and the monocross suspension already in force on the YZ125F and YZ250F 4-T. New, wider footpegs, as well as rear disc and caliper protection are also part of the new parts list..

The YZ125 and YZ250 will be available from September, while the YZ85 will be delayed until December 2014. Their prices, however, are not yet known: stay tuned !

YZ250F and YZ450F: what changes in 2015

Deeply revised (including the adoption on the 250cc of the "inverted" engine architecture discovered on the YZ450F 2010), Yamaha’s 4-stroke range only logically evolves in detail for 2015. 

Insofar as their competitiveness is no longer to be demonstrated (8 consecutive podiums in the 2014 world championship for the 450, while the 250 shines in both MX US and MX2), this relative "immobility" can be perfectly understood..

The main changes therefore affect the trim, sharper and benefiting from new black rims, as well as the way in which the single cylinder delivers its power on both motorcycles..

The injection and the ignition are modified in order to obtain a more regular power supply – and therefore more exploitable – on the nasty YZF450 and more fishing at mid-speed on the nervous YZF250. In addition, the throttle opening control is lightened on both motorcycles, while the bolts used to hold the air filter cover are advantageously replaced by quick-release fasteners. A welcome change for maintenance operations. 

Finally, the 250 benefits from an easier starting thanks to the new profile of the camshaft, while its piston has been redesigned to improve its performance..

The YZ250F and YZ450F will be available from July in the, at prices not known at this time. To follow naturally on MNC: stay connected !

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