Looking at the 2012 Kawasaki KX250F it appears Team Green forgot all about the small-bore four-stroke while revamping the 2012 KX450F. While its big brother got updated plastics, a smaller gas tank and an electronic launch control, to the naked eye not much is new with the 249cc motocross racer. However, looks can be deceiving and Kawasaki did not rest on its laurels. Updates for 2012 include a second fuel injector, revised spring rates and damping, an upgraded crankshaft and changed transmission internals. On top of that a few blue anodized parts mimic the factory race team. For all the technical details check out the 2012 Kawasaki KX250F First Look Article.
Kawasaki invited us out to The Ranch motocross facility for a first ride on the 2012 KX250F. Two tracks at the park were at our disposal to flog the small bore racer. The MX Pro track is a mix of loam and sand and fairly smooth with a three-pack of uphill doubles requiring a strong running 250 to clear. Next to the main track is a reproduction of the famous USGP Carlsbad track that is very close to what I remember, although the hills are not as steep. It even has the hard-packed, pothole chop that the raceway was infamous for. With these two tracks, our in-house pro Chis See and I had more than enough terrain to make a fair assessment of the Kawasaki.
The dual injector set of the Kawasaki KX250F produces a strong mid-range hit, more top-end and increased over-rev.
The most notable change to the 250F is the use of two fuel injectors to increase top-end and over-rev performance. One injector is in the 43mm throttle body, while the second is upstream in the airboot and delivers an extra shot of go-juice on acceleration. Immediately we could feel the difference throughout the entire rev range. Our resident ripper See rides much higher in the rpm than I and felt the improvement on the top-end was substantial. He could also use the increased over-rev in some of the shorter chutes rather than grabbing another gear. Both of us also felt the low-end was slightly better, especially when pulling out of a loamy berm, but the most effective way to ride the KX250F was to keep the revs up and use the meaty mid-range all the way to the redline.
As you may have noticed I outweigh most test riders by a solid 40 if not 50 lbs, but the grunt coming out of the KX still allowed me to clear the uphill doubles on the Pro Track, even though I had my doubts at first. Just a quick flick of the clutch immediately puts the Kawi right in the torquey thrust available from the 250F’s mill. On the Carlsbad Track the rush of power as the revs climbed made quick work of the long straightaways, and the raspy exhaust note ringing in my ears let me know when it was time to grab another gear. It’s not a quiet bike by any means although Kawasaki claims the level to be 94db. In all we would have to say revisions and additions to the KX250F motor are going to be hard to beat when it comes time for our annual 250 Motocross Shootout.
Last year the KX250F was knocked down during our shootout for a transmission that was notchy and difficult to shift under power. The engineers took note and have thrown a few tweaks into the Kawasaki’s gearbox. The stroke of the shift fork has been shortened and the shift rods are now solid rather than hollow in an effort to smooth out the shift action. The long uphill sections of the Carlsbad course was perfect for testing full power upshifts and the transmission worked much better than the 2011 model. We still think it could be a little easier to click the gears under load, but the engagement was always solid. I did find neutral once downshifting into a corner, but it was an isolated event. Clutch action was light and smooth, however after 30 minutes of abuse from See the clutch began to fade. Once cooled down, all was good.
For 2011 Kawasaki went with Showa SFF (Separate Function Fork) suspension up front that split the spring and damping duties to one side of the fork for each. The right fork houses the spring and has the only external preload in the 250 class while the left handles the compression and rebound damping. This allows for a wide range of adjustability, as the spring load has a marked effect on the handling from the fork. For 2012 Kawasaki increased the spring rate from 9.1N/mm to 9.5N/mm and made the rebound spring longer. The valving of the left fork’s damper stack has been revised to work with the stiffer spring rate of the right fork.
In the rear, the Showa piggyback shock also receives a stiffer spring, going from a 51N/mm to a 53N/mm. Once again the damping was revised for the heavier spring, and the internals were refined. The linkage tie-rod was thinned in an effort to reduce rigidity and increase rear wheel traction.
Setting up the suspension was rather quick for See, and he was dialed after just a couple return trips to the mechanic’s area. From the stock setting he went three clicks stiffer on the compression and two faster on the rebound while leaving the preload untouched. On the shock, the sag was set at 103mm, and went two clicks to the right on the low-speed compression and a quarter-turn to the left on the high-speed adjustment. The rebound was left at the stock setting.
The soft initial stroke of the SFF front end lets the 2012 KX250F turn in easy but requires aggresive cornering to keep the bike leaned over.
For See the front fork was soft on the initial part of the stroke and then got harsh in the mid-stroke, but the SFF had good bottoming resistance on the big jumps. The softness of the fork made the KX250F turn in easy, but once in the corner the bike wanted to stand up if not ridden aggressively. The changes to the rear end helped the bike track excellent in a straight line no matter how chewed up the track was, and the rear would drop into the corners and increase the stability coming out on the power. Overall Chris felt the harder you rode the better the suspension got.
Right off the bat we reset the sag to 106mm for my 225-pound frame, and after one lap we increased the shock low-speed compression three clicks from See’s setting and returned the high-speed compression to the stock position.
That was enough to help the KX track straight and soak up the hard hits that my girth tends to inflict in the rear shock as I pound through the chop. I stuck with the same fork setting as our featherweight pro. The Ranch is full of soft powder berms on the outside and slick hardpack on the inside of corners. The 250F handled either choice and allowed my confidence in the front end to increase quickly. Exploding berms or squaring off the inside, the choice is yours and both are excellent. I did not have a problem with the bike wanting to stand up in the corners, however I am much larger and muscle a bike in the corners rather than using finesse like See. On the higher speed sections of the track, the KX250F tracks true and never shakes its head, and on the brakes the chassis is just as settled. Overall we have to say the handling and suspension has improved for 2012.
The cockpit of the 2012 KX250F is unchanged for from last year’s model, so it was immediately familiar. As one of the most comfortable machines in the 250 class, the Kawasaki will fit a wide range of riders. I prefer moving the handlebar mounts forward to suit my desert-racer style, while See goes Ricky Carmichael putting everything far back as possible.
The seat is wider and thicker than some of the other machines in its class, but the sides of the seat offer excellent grip for your knees. The body work is smooth and doesn’t hinder movement.
We would have liked to see the 2012 model receive the same styling update as the KX450F; its unchanged looks betray the improvements in performance that have been achieved with just a handful of changes. Kawasaki has polished and tweaked the KX250F, but is it enough to take the crown as the best small bore MXer? In a class that is so fiercely contested, just a small improvement can pay big dividends. We’re betting that the 2012 Kawasaki KX250F will be at the top of the list for our testers when our 2012 250 Motocross Shootout rolls around.