Adam Booth | September 8, 2016
Let’s get straight to the point: The all-new 2017 Kawasaki KX250F is better than the 2016 KX250F. It is sleeker, 3.75 pounds lighter, and more powerful; all qualities that help you go faster on the motocross track.
Some bikes jump, but the 2017 Kawasaki KX250F flies. It’s lighter and more agile than before.
Not that Kawasaki needs to go faster, their record of 16 AMA Championships with the KX250F is stunning. The KX250F has also claimed 48% percent of AMA Motocross National wins since 2004 (a stat provided before the end of the 2016 season). Still, who doesn’t want to go even faster? The folks at Kawasaki certainly do.
To read this story in Cycle News Digital Magazine, click HERE
Photos by Adam Booth
Plethora Of Change
Kawasaki made a lot of changes to the all-new 2017 KX250F, and not all of them were made to just the engine. The whole bike got some attention. The KX250F was already a fine motorcycle and there wasn’t too much to complain about, really. But in the never-ending quest to make motorcycles lighter, faster, better handling and more comfortable, the ’17 KX250F got a fairly significant overhaul.
The frame is 6mm narrower and closely resembles the design of the 2017 KX450F frame. It now has a one-piece forged down tube and narrower extruded side spars for improved flex characteristics. A new lower triple clamp compliments the frame changes and is thicker, offering more clamping surface. It is a shared part with the KX450F. The new frame, along with a new lower gas tank (10mm lower at the gas cap) allows the seat to be flatter where it meets the tank.
The swingarm is new and the same as the 2017 KX450F, which means the dog bones in the linkage are .5mm longer and the bell crank is revised as well, providing a more progressive ratio.
Like the KX450F, the “little” KX250F is slimmer and more comfortable between your legs.
The most important component in a 250F is the engine and Kawasaki reworked the KX’s engine with seven-degrees more cylinder offset for a more direct line to the intake. The cylinder now features plateau honing and journal-type bearings instead of needle bearings at the big end of the connecting rod. The combustion-chamber configuration is also revised for more efficiency. A new lighter race-based piston with bridged-box bottom now has a molybdenum coating on the outer surface, reducing friction and as we all know, less friction means more power. Titanium valves (very light) are operated by a revised exhaust cam with increased lift.
Kawasaki is still using dual injectors, but for 2017 those injectors have a new angle, providing a more direct shot into the cylinder. The spray of fuel is more in line with the direction of airflow, again, increasing power. Eight holes instead of four on the downstream injector creates a smaller droplet size and better atomization.
A lighter flywheel helps drop the overall engine weight. It is now 1.5 pounds lighter than last year. With all the engine changes, Kawasaki updated the ECU settings for 2017 and still offers the quick-change map couplers. Improving reliability and function, the shift forks have a better heat treatment and a new shape. For smoother shifting, needle bearings have been added to support the shift shaft.
Over the recent years, the KX250F has improved immensely when it comes to cornering. The 2017 version is the best at it yet.
The 2017 KX250F doesn’t get air forks, it retains the Showa SFF-2 fork, a single-sided spring fork. Revised valving and a stiffer spring rate aims to improving damping and overall balance. Forty clicks of preload adjustment offer a lot of set up options. Out back, complimenting linkage ratio and swingarm changes, the shock gets a new lighter shock spring with a lighter spring rate.
On The Track And In The Dirt
Right off the stand, the KX250F kicks to life incredibly easy. Almost zero force is required to move the kickstarter through its arc and ignite the engine. Thanks to the lighter flywheel, intake changes and engine updates, the 2017 engine revs quicker than the 2016 model. It also feels more powerful, with stronger pull off the bottom and through the mid. Top-end power is still impressive and a strong trait for the KX250F. It doesn’t have quite the top-end pull of the KTM 250 SX-F or the Yamaha YZ250F, but it pulls nicely in the upper rpm.
Riders who like to use an engine in the midrange will appreciate the KX250Fs power delivery. We played with the different couplers and always gravitate back to the stock green coupler, finding it provides the best power throughout the rpm range. Shifting is smooth and the gear spacing is well matched to the power. The exhaust note is classic Kawasaki, raspy and on the loud side.
When it comes to overall handling, the all-new 2017 KX250F isn’t quite as stable as the 2016 model, but the new quicker handling and easier turning traits are well worth a slight loss of stability for a bike that was king of the stability category anyway. For 2017 the KX250F has better front-wheel traction thanks to the frame, suspension and triple clamps revisions. The KX250F is traditionally a rear-end steering bike and having more front-wheel bite is a welcome addition. Also contributing to the ability for the front end to grab traction is the switch to the Dunlop MX3S tires, which we feel work much better than the MX52.
(Right) Not much to complain about here. If you’re a low-to-mid person, you’re really going to like the KX’s power delivery. (Left) New linkage ratio, swingarm and shock do wonders for the KX’s rear suspension.
The 2017 KX250F is 1.3 inches narrow from radiator shroud to radiator shroud, a big contributor to the very narrow feel. The seat is also much flatter leading into the lower gas tank, creating an ultra flat seating position. Sliding forward for corners on the KX250F is very easy. The lighter overall feel of the KX250F also makes it easier to corner. Laying over into ruts and trusting the front wheel is much easier now.
The suspension changes have helped further balance the KX250F. Compliance over small chop is better and keeping a consistent arc through corners is improved. Keeping the sag around 105mm worked best for us. To little sag, around 100mm actually made it feel a little twitchy up front, a trait never experienced from previous KX models. Some testers familiar with previous KX models liked as much as 110mm of sag, depending on the track conditions.
Just lean it over and gas it. The KX won’t mind if you do.
Better Or Worse?
With a good amount of track time aboard our 2017 KX250F test bike, there is no doubt the changes Kawasaki implemented have created a better KX250F. It is lighter, faster, narrower and better handling. CN
Here’s what it’s like to take a lap around Zaca Station on the 2017 KX250F.
PROS
Improved power
Better chassis and better cornering
Wide range of adjustability
CONS
Loud exhaust
Fast wearing chain guide and slider
GEAR ID’D
GEARSET: Answer Syncron
HELMET: Scorpion VX-R70
GOGGLES: EKS Brand
BOOTS: Sidi Crossfire 2/Alpinestars Tech 10
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SPECIFICATIONS: 2017 Kawasaki KX250F
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Engine Type:
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249cc liquid-cooled DOHC 4-stroke; 4 titanium valves
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Bore x Stroke:
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77.0 x 53.6mm
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Compression Ratio:
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13.7:1
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Fuel Delivery:
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DFI 43mm Keihin throttle body dual injectors
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Ignition:
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Digital DC-CDI
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Transmission:
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5-speed; multi-plate wet clutch
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Final Drive:
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Chain
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Front Suspension:
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48mm Showa SFF-2 separate function fork, 12.2-in travel
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Rear Suspension:
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Uni-Trak linkage, Showa rear shock, 12.2-in. travel
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Front Brake:
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270mm Braking pedal-style disc w/ two-piston caliper
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Rear Brake:
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240mm Braking pedal-style disc w/ single-piston caliper
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Front Tire:
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80/100-21 Dunlop MX3S
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Rear Tire:
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100/90-19 Dunlop MX3S
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Seat Height:
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37.0 in.
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Wheelbase:
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58.1 in.
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Ground Clearance:
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12.6 in.
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Fuel Capacity:
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1.69 gal.
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Claimed Wet Weight:
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229.9 lbs.
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Color:
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Lime Green
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MSRP:
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$7,749
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To read this story in Cycle News Digital Magazine, click HERE
For more Cycle News Motocross motorcycle reviews, click HERE.
For more Kawasaki motorcycle reviews, click HERE.
