The YZ250 was already known for its solid handling, excellent suspension and outstanding durability, but the YZ’s motor was getting a little long in the tooth and was in dire need of a makeover, and it certainly got it.
Yamaha’s development target with the new YZ250F was to improve mid to high rpm performance without losing bottom-end torque feeling. To do this, Yamaha started from scratch and designed a completely new motor. Internally, pretty much everything is new. It has a new four-valve cylinder head that uses a straight-port downdraft design. It has new intake and exhaust valves, camshafts, piston, transmission ratios, clutch and wet sump design. Yamaha claims the new YZ250F has more midrange and top-end power, more over-rev power, smoother shifting and overall improved controllability. And the new 12-hole fuel injector provides more consistent throttle response.
As seen on the YZ450F factory motocross race bikes, the YZ250F is fitted with a wrap-around exhaust system, which enables the silencer to be mounted a whopping 7.5 inches closer to the center of the bike. The overall design of the exhaust system better centralizes mass weight resulting in a lighter feel on the track.
Although the frame is new, its dimensions are still similar to the previous frame, which was already considered one of the best in the business. It was so good, that the all-new WR450F, which came out in 2012, was fitted with the same frame. The 2014 chassis has new engine brackets, new rubber-mounted bar mounts, and allows for a new center positioning for the fuel tank, which has more capacity at 2.0 gallons (formerly 1.6 gallons). The thickness of the frame’s main rails is different for what Yamaha translates into improved rigidity balance.
No air forks for the Yamaha. Instead, they stuck with its highly praised Speed Sensitive System KYB forks, but it does have a new surface finish for the inner tubes, and the outer tubes have been modified for different rigidity.
To accommodate the new fuel tank and exhaust system, the shock’s reservoir is mounted vertically instead of horizontally.
Speaking of the fuel tank, missing is the fuel cap. Well, it’s not really missing but it’s now hidden under the seat, making for a flat and uninterrupted layout along the top of the seat and the wrap-around radiator shrouds. The fuel cap is located in the same general area but underneath the front part of the seat. For tool-less access, you remove a small portion of the seat, revealing the cap. The small part of the seat that you just remove is tethered to the bike so you can’t lose it and snaps back into place. This design adds one more step to the refueling process, so off-roaders might not like it, but Yamaha designed this bike with motocross in mind and will remind you about their WR line.
On the flip side, however, Yamaha made access to the air filter easier. It’s now a two-step process instead of four.
As before, the YZ250F will be available in two color choices – Yamaha Race Team Blue/White, and White/Red. The white version also has black rims and a gold chain.
Yamaha’s accessory GYTR Power Tuner is compatible with the YZ250F.
Yamaha announced an MSRP of $7490 but the bike won’t be available until October.
SPECIFICATIONS: 2014 Yamaha YZ250F
Liquid-Cooled, DOHC, 4-Valve, 4-Stroke
BORE X STROKE:
77.0 x 53.6mm
Yamaha Fuel-Injection (YFI), Keihin 44mm
Constant-mesh 5-speed, wet multi-plate clutch
KYB Speed-Sensitive System, inverted fork, fully adjustabl
KYB single shock, fully adjustable
FRONT WHEEL TRAVEL
REAR WHEEL TRAVEL:
Hydraulic single disc, 250mm
Hydraulic single disc, 245mm
80/100-21 Bridgestone M404-A
100/90-19 Bridgestone M403
Team Yamaha Blue/White; White/Red
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