Kawasaki has more professional Lites-class championships than any other manufacturer. In the hands of accomplished race teams, the KX250F is obviously a podium threat. For 2011 it looks as if that trend will continue as Kawasaki has added even more technology to the KX-F. It went to the drawing board in the offseason and started by borrowing the digital fuel injection from its 450. The 43mm throttle body has an injector with 20% higher flow rate to feed the higher-revving 250. It also gets a new cam profile, increased compression from the bridged box-bottom design piston and adjustments to the intake and exhaust. The head pipe is longer and the muffler has increased volume which helps boost low and mid-range power while keeping the decibels under control. It was second-quietest in our test at 92dB.
All of our riders were happy with the Kawasaki’s new fuel-injected engine and it backed that up with a strong showing on the dyno. We had more than one rider accuse Mitch Payton of tinkering with the internals, that’s how fast the KX-F is. Plenty of power across the board makes this bike stand out in the 250F division and that’s becoming increasingly difficult to do. Our pro tester, See, laid down his fastest time around Racetown 395 aboard the green bike. Acceleration testing showed a 4.92-second holeshot time and 3.12-second roll-on. Both are within almost a tenth of a second from the top-two spots. Kawasaki did not receive high marks in 2010 for its drivetrain and the same goes for ’11. All of the bikes shift extremely well but the Kawasaki is a little clunkier than some and it can’t compare to the fluidity of KTM’s hydraulic clutch. Several of our testers love to complain about clutch fade, and here the Kawasaki stood up to their abuse. A new 50-tooth sprocket, compared to the 48-tooth of old, helps make sure the pilot doesn’t have to slaughter the clutch.
Equally big news comes from the Showa suspension package where an all-new Separate Function Fork adds the element of tunable spring preload. The spring is housed in one fork leg and the valving is handled in the other. This new setup allows the bike to easily change handling characteristics. Kawasaki says the new Showa settings are aimed at “race-experienced riders.” From our intermediate to our oldest pro, the Kawasaki ranked highly for its new SFF and shock. Faster, more aggressive riders enjoyed the suspension package and that worked in its advantage with our larger crew. The KX-F was second only to the Honda which is untouchable on the small chop. For as revolutionary as the SFF feature is on a production motocross bike, the KF-X feels like an aggressive, well-suspended motorcycle. We spent much more time with the compression and rebound clickers than with the preload, but our tracks were mostly higher-speed. Switching between tight and open layouts will see the biggest gains from this new feature.
Handling gets overshadowed by the potent engine, but the Kawasaki is good in the corners and nimble in the air.
Handling is well regarded also with a new steering geometry of 28.2 degrees rake and 4.7 inches of trail. The new fork has 1mm less offset (22.5mm) and a slightly longer swingarm to accommodate the bigger sprocket, which lengthens the wheelbase to 58.1 inches. The new combination brings a blend of stability and agility. Our crew especially likes the way the rear end behaves with a very stable and predictable platform. Ergonomically it’s right in the middle of the road. Our testers are fairly tall and the Renthal handlebar was noted for additional comfort. Compact riders consider the Kawi layout to be very open and roomy. Braking is another category where our testers were lukewarm. Outright feel at the front lever is lacking but overall stopping power is more than adequate, as are all the machines.
Horsepower is the first thing our testers want to talk about when discussing the Kawasaki. Some couldn’t discern the top-end pull, but the dyno charts show a distinct surge in the final 500 rpm where the other bikes fall off, making it one of the most well-rounded powerbands of all. But aside from the impressive engine, the KX-F scored a run of third-place votes and a couple second-place tallies in the other categories. Just one or two more standout features and the Kawasaki would be topping this shootout.
2011 Kawasaki KX250F Rider Impressions:
Tod Sciacqua – 5’8 – 170 lbs – Vet Expert
I loved the Kawasaki right when I sat on it. That motor was amazing, and really that’s what counts in this class. If you have a stronger motor you can holeshot and win races – the Kawi was my pick for the motor. When I pulled in I swear I thought it was a cheater motor. I can’t wait to see what the dyno has to say. It handles great, and the ergos are perfect for me. The SFF suspension works fine but I’m more likely to adjust my riding style to fit the bike. The KX250F was easy for me to get comfortable on and go fast.
Brian Chamberlain – 6’0 – 190 lbs – Vet B
I really developed a liking to the KX250F after a few days of testing. The ergos suit taller riders so I felt very comfortable with the layout. The Renthal bars have a good bend and felt a little wider and taller than most of the other bikes. The standout feature of the KX has to be the motor. The KX starts to shine in the mid-range and continues to pull hard all the way through the top. The bike felt like it could rev forever and continued to build power the whole time. I really like the long revs whereas some of the other bikes power delivery falls off a little early for my tastes.
The suspension works well for my speed and weight, although the fork is not as plush as the Honda. It’s a little harsh through the braking bumps, but some adjustments started to get it in the right direction. The shock felt good right out of the box. Other than setting sag, no adjustments were needed. It soaks up the big hits and stays settled through the high-speed bumps.
Another area the Kawi stands out is handling. I love the way the bike steers. I’m able to get it turned in whenever I want and it adapts well to steering input at both low and high speeds. Fit and finish are average while the componentry are a little above average. I like the coated forks, anodized clamps, wheels and other bits.
Chris See – 5’10” – 160 lbs – Pro
I was probably most excited to try this machine with it having new forks and fuel injection added to it. I must say that it did not let me down one bit. The fork on the green machine is valved well, but it’s a little soft for me so we went four clicks stiffer on compression and two faster on the rebound. Half a turn slower on the rear end high-speed compression and after these few changes the bike was set up pretty well.
As for the fuel-injected engine, it feels as if this bike has motor work and the others are in stock form. The transmission is very notchy though and is hard to shift under power. Kawasaki also has a very good clutch feel on this machine and not a ton of clutch fade which is great. I did notice a questionable amount of rear brake fade, where the front works well. Overall the Kawi is a class leader to me and sitting right on the border of first place in my book.
Kyle Lewis – 5’10” – 180 lbs – Vet Pro
I am surprised with this bike! The motor is quite a bit stronger than all the others. It almost feels like a PC motor! All kidding aside, overall the motor feels strong. I wish the transmission spacing was a little better. Second is very close to third, but there’s too much of a gap up to fourth and the rpm drops too much. It makes me use the clutch quite a bit but at least that is strong – grabby, but durable.
Unlike its big brother I am able to turn this bike a little easier. I feel stable through high speed corners and can steer the bike with the rear wheel. I don’t like the way it tries to tuck under in tight corners and it still feels a little wide and long for my liking. It’s funny, I don’t like the front brake on the KX450F, but I like the front brake on this bike? It could be because the 250 is lighter. No complaints with the suspension and overall I’d put this bike second.
Nick Thiel – 6’1” – 175 lbs – Intermediate
The standout on the KX-F is the motor. It pulls hard and revs fast. It signs off a little early up top for me but still works awesome. The overall handling was good other than a little bit of high speed nervousness in the front end. With the limited amount of time on the bike I had its hard to say it wasn’t just a small setup issue. The clutch is awesome with very little fade and I always love the feel that Kawasaki has on its brakes.
Getting the KX250F slowed down is one of the weak areas. Fortunately, unlike its big brother, the 250 offers a large layout without carrying excessive weight.
JC Hilderbrand – 5’11” – 177 lbs – Novice
At first I didn’t think the Kawi was any faster than the others, but after getting it on multiple tracks the motor really proves itself. It’s pretty beefy all around, but there’s a flat spot on top and it won’t pull all the way until redline. I’m talking about a small spot and I shift way before that anyway most of the time. It revs very fast and has the most vibration. We didn’t have much of a need to change the fork preload, but I’ve messed with it enough to know that this is a cool feature. I’m more concerned with the valving and both ends feel really stiff. It just likes to go fast and slam into things, which is good for speedy guys. I couldn’t find a happy spot until a couple days of testing.
Kawasaki chooses a good Renthal handlebar but it has a squishy seat. That helps keep you in place and is by far the most comfortable, but ultimately I liked the stiffer Suzuki and Honda platform. I also don’t like the way the Kawasaki sounds. It makes you feel like you’re going fast I guess, but can’t they fix that muffler? One thing that nags me about the KX-F is that it just doesn’t feel tight – like the manufacturing tolerances aren’t as close as other brands. The exhaust is loud and kind of rattling, it vibrates, fork action is loose – it’s lacking a polished feel. That’s a pretty intangible thing and when it comes down to it, there’s no denying that the Kawasaki is one of the straight-up fastest bikes this year.