Yamaha’s 2014-spec YZ250F is now on sale across Australia, and the manufacturer says it sets a new benchmark in quarter-litre motocross performance.
Headlining the changes is the adoption of a reverse engine layout, as found in its open-class sibling, the YZ450F. Now fed by electronic fuel injection, the reverse layout means the intake tract is straighter, boosting performance, while the format also aids mass centralisation.
The engine now has a more compact combustion chamber and a DOHC, four-valve head, the latter with narrower valve angle. A new two-ring piston design minimises weight and friction losses, says Yamaha, while the offset cylinder design reduces friction too.
Yamaha’s accessory Power Tuner, a hand-held device, allows riders to adjust ignition timing or the fuel injection system, thereby allowing modifications to harness a variety of performance parts like exhausts.
All up, Yamaha says the 2014-spec machine produces between 3.7-4.4kW more than its predecessor.
Significant efforts have been made in mass centralisation to enhance the bike’s handling and agility. The fuel tank has been moved back while the muffler has been moved forward.
The chassis is all new, comprising 10 different forged, cast and extruded aluminium components.
The new frame is complemented by revised suspension settings front and rear, while a ‘slimline’ body design and thinner radiator further reduce weight.
The new model also features a number of practical revisions, with easy access to the air cleaner and a fuel tank that can be lifted up and rotated 180 degrees to rest on the rear frame, without requiring the disconnection of any hoses. The tank’s capacity has been increased from 6.4lt to 7.5lt.
Yamaha claims a wet weight of 105kg for the new model.
The 2014 Yamaha YZ250F is available in Yamaha Racing Blue for $10,999 or Competition White SE for $11,099. The model is covered by a three-month parts warranty.