After has spent a lot of time on muddy tracks and harsh terrains, the old Yamaha YZ250 was blessed with a complete upgrade in 2010. The bike entered in 2011 without any changes, but the year 2012 has brought a new series of upgrades which help it remain at par with its rivals.
The YZ250F is one of the best looking small bore bikes in its class and we’re glad to see that Yamaha decided to keep the overall designed unchanged. Most of the upgrades were to the engine, frame and chassis, so all the action took place under the skin. Thanks to the new tweaks, the engine’s power was increased in the upper rev range. On the other hand, the upper frame rails have been changed from a two-box section to a three-box section to control flex, while the cast swingarm section and the engine brackets were also modified.
Find out more about the Yamaha YZ250F after the jump.
The optimized engine pumps out power in the 8,000 to 12,000 rpm range with outstanding throttle response, thanks to crankshaft webs, vibration-reducing counterbalancer, connecting rod, and low-friction piston rings, as well as a new piston, piston pin, and clip assembly that’s over 8% lighter overall than before. To take full advantage of these advancements, there’s also CDI mapping and a big 39mm carb with free breathing air cleaner cage. Added to the frame and suspension refinements, this latest engine gives YZ250F amazing balance – a powerful, light-handling machine with performance that’s accessible to all levels of riders.
The Bilateral Beam frame has a rigidity balance for superior cornering performance as well as great stability on rough, high-speed straights. Beefy front suspension components plus rear shock internals and rigidity in the swingarm axle block area give this machine a serious handling advantage with light, quick steering.
The styling emphasizes the bike’s lightweight and nimble handling character. The sharp, horizontal lines set the bike apart with a clean, aggressive look.
KYB® suspension is tuned to work with the Bilateral Beam frame for unmatched handling.
There’s no disputing the YZ250F’s unmatched four-stroke prowess – it was the 1st four-stroke 250 motocross bike on the market, the 1st to win an international race, the 1st to win an AMA® Supercross,® and the 1st to take an AMA® U.S. Supercross Championship® title, as well as the ﬁrst to win an AMA® National race.
Riders have a choice of two color options: Team Yamaha Blue/White or White/Red.
The valve spring retainers are lightweight aluminum instead of steel, and light valve spring pressure reduces valve-opening force. Valve stem ends are chromium-nitride coated for exceptional reliability and reduced maintenance.
The exhaust port is “D” shaped instead of round. This increases velocity through the port for excellent throttle response, while enhancing the power feeling of the engine.
The air cleaner cage design provides increased airflow, contributing to the excellent throttle response in the mid-to-high speed range.
The low-mounted radiator is as far back as possible and the compact oil tank is positioned to achieve greater mass centralization.
The 39mm carburetor has a venturi-shaped bore, plus recalibrated jetting and an accelerator pump. This translates to impressive response when the rider snaps open the throttle, and contributes to superb mid-to-high-rpm power characteristics.
The intake boot offers a straight, smooth tract for excellent engine breathing and more power. The airbox is shaped to tuck neatly into the Bilateral Beam frame.
The exhaust pipe has been carefully tuned to optimize engine power, with a muffler that meets 94 dB standards.
The Bilateral Beam frame is crafted from a carefully chosen combination of forged and extruded aluminum pieces, all welded together to provide unmatched rigidity balance and superb cornering characteristics, as well as excellent handling on rough, high-speed straights.
The KYB® speed-sensitive front forks deliver exceptional damping feel, responsiveness, and bump absorption characteristics.
The 4-way-adjustable KYB® rear shock makes the most of the latest Bilateral Beam frame design. It’s low in the frame for excellent mass centralization, with a 16mm shaft and settings for optimal hydraulic flow.
The YZ250F has beefy outer fork tubes and triple clamps. The result? The front fork assembly’s torsional rigidity for unmatched chassis stability.
Fork offset is 22mm to accommodate the frame design. This shortened offset increases trail length which, in turn, contributes to excellent stability and reduces the inertial moment of the front fork assembly for quick, race-winning handling. The rider can take advantage of the higher level of performance throughout the turn.
The axle block portions of the swingarm provide greater rigidity to further optimize the rigidity balance between the frame and the revised front fork assembly.
The tank, seat, and rear fender are flat and the relationship between handlebars, pegs, and seat result in a natural, more forward riding position that facilitates rider movement. The fuel tank is placed toward the center of the bike for mass centralization. The aluminum tapered handlebars are 4-way adjustable, and handlebar mounts and foot pegs optimize rider position on the chassis.