2014 Yamaha YZ250F | Motocross Motorcycle Test

2014 Yamaha YZ250F | Motocross and Off-Road Motorcycle Test

The highly competitive 250 four-stroke motocross market requires manufacturers to constantly up their games with new innovative designs to differentiate themselves from their rivals. For 2014, the Yamaha YZ250F is new from the ground up, making it one of the most anticipated bikes of the year.

The all-new machine features a redesigned motor—fuel-injected for the first time– plus a new aluminum frame design, revised suspension components and settings, as well as a new layout for the exhaust, airbox, gas tank, and seat.

Yamaha has adopted an engine design for the 2014 YZ250F that is similar to its larger bore counterpart, the YZ450F. The new fuel injected motor—with a Keihin 44mm throttle body—features an all-new four-valve cylinder head (all four valves are titanium) with the intake/exhaust layout reversed compared to the traditional style.

This change allows for a straight downdraft intake tract, providing a direct entry path for the incoming air/fuel mixture. This is matched with a straightened exhaust port placement for maximum efficiency. A new two-ring piston that is both shorter and lighter than its predecessor, compresses the charge. Updated camshafts make all of this happen at the right time.

The new exhaust layout with length and shapes optimized for best power delivery, wraps around the cylinder moving the silencer much closer to the center of the bike, while still keeping the head pipe short enough for optimum top end power output. This design allows the muffler to move forward by 7.5 inches, which also reduces the size and weight of the subframe. This combined with engine placement that rotates the cylinder position rearward by 4+ degrees, is all a part of an overall push by Yamaha to improve handling by centralizing the weight mass.

Along with the new motor design comes a new chassis for the YZ250F. The aluminum bilateral beam frame is designed to provide a compact, lightweight feel while maintaining stability. The larger 2.2-gallon fuel tank has also been moved rearward for mass centralization purposes.

The KYB forks have new inner and outer tubes, with special coatings and polishing to minimize stiction. The KYB shock reservoir location, spring rate, and damping specs have been revised to enhance the feel of the new chassis.

So, how do all of these changes play out on the track? Having ridden most of the other 250Fs, I was eager to put the new Yamaha to the test.

The first thing I noticed was the YZ250F’s powerful motor. The fuel injection provides smooth, instantaneous power off the bottom end that is perfect for exiting corners. The bike really comes alive in the high speed sections of the track with impressive mid- to top-end power. Yamaha also offers an optional GYTR Power Tuner that allows you to tailor the power delivery to your liking.

A slight downside to the powerful new motor is that the bike is a little harder to start than other 250Fs. The new transmission, designed to minimize frictional power losses and provide smoother shifting, worked very well, providing easy and precise gear changes with perfectly split gear ratios.

After setting the Yamaha YZ250F’s sag to suit my weight—about 155 pounds—the suspension felt plush and compliant on a relatively smooth track like Milestone MX Park in Riverside, Calif. Over-jumping or coming up short in bigger jumps is no problem for the KYB Speed-Sensitive System forks and KYB shock.

The YZ250F feels really planted in the rutted corners, but has a tendency to dance around a bit on the acceleration bumps. The rear shock works great for seat-bouncing jumps out of tight corners. Through the whoops, the front end is very light and manageable, while the rear shock kept the rear wheel planted on terra firma, maintaining good traction. On a rougher track like Zaca Station MX Park in Buellton, the KYB suspension initially felt a bit harsh through the braking bumps, but some minor clicker adjustments quickly resolved the issue.

The Yamaha felt very light and nimble through the technical sections of the track. Yamaha’s mass centralized design makes the bike easy to turn, changing direction with minimal effort, especially in tight ruts. On smooth, flat corners, the front end felt a bit unstable, until I took advantage of the new seat/gas tank design. The fuel filler cap has been relocated underneath the front of the seat, making it easy to get over the front of the bike and transfer more weight to the front wheel.

I really like the layout and feel of the 2014 Yamaha YZ250F’s cockpit. The powerful, but progressive, front disc brake is easy to modulate, allowing you to efficiently brake later and push deeper into the corners. As a professional trials rider, I have a well-developed sense of how the clutch should operate and this one delivers nicely. Precise engagement and smooth lever pull provide perfect power delivery when exiting corners.

On the maintenance side, a new air filter location behind the steering head keeps the air filter tucked away from roost and makes it easy to access for cleaning. Unfortunately, this change comes at the expense of the bike feeling slightly wider than its competition.

As with any complete redesign, I had my reservations about this first generation bike. Overall, I am very impressed with the 2014 Yamaha YZ250F. Whether it’s hitting a rutted jump face, wide open on a long straightaway, or leaned over in a tight rut, the new Yamaha YZ250F does it with ease, and in the process imparts a great sense of confidence to the rider.

Riding Style
Helmet…Shoei VFX-W Sear TC-2
Goggles…Scott OTG
Neck protection…Leatt-Brace GPX Race
Chest protection…Leatt-Brace Pro
Jersey and pants…Axo Lightning
Gloves…Novik T.E.C. Darkness
Boots…Axo Dart Pro

Photography by Don Williams

2014 Yamaha YZ250F Specifications

Engine Type…249cc liquid-cooled DOHC 4-stroke;
4 titanium valves
Bore & Stroke…77.0 x 53.6mm
Compression Ratio…13.5:1
Fuel Delivery…Yamaha Fuel Injection (YFI), Keihin® 44mm
Ignition TCI
Transmission…Constant-mesh 5-speed;
multiplate wet clutch
Suspension/Front…KYB Speed-Sensitive System, inverted
fork; fully adjustable, 12.2 inches of travel
Suspension/Rear…KYB Fully adjustable single shock;
12.4 inches of travel
Brake/Front…Hydraulic single disc brake, 250mm
Brake/Rear…Hydraulic single disc brake, 245mm
Tire/Front…80/100-21 Bridgestone M404-A
Tire/Rear 100/90-19 Bridgestone M403
L x W x H…85.2 x 32.5 x 50.4 inches
Seat Height…38.0 inches
Wheelbase…58.1 inches
Ground Clearance…12.8 inches
Fuel Capacity…2.1 gallons
Wet Weight…231 pounds
Color Team Yamaha Blue/White; White/Red
2014 Yamaha YZ250F MSRP…$7490.


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