After riding my Ninja ZX-6R for a time, I began to think about riding a smaller bike; something I could just take out anytime, anywhere, with a minimum of hassle and maintenance. Originally I thought of just getting a trail bike like a Kawasaki KLX140L, but once I was at Florida Motorsports in Naples I spotted the blue 2010 KLX250SF and I knew this would be the ideal solution. It just looked so cool, especially with the bright blue finish on its RK Excel wheels that reminded me of the anodized rims on BMX bikes from the 1980s. So I made a deal on it and the new KLX was delivered the next day and my adventure with this supermotard-inspired thumper began.
I’ve now had my 250SF for more than a year and I’ve put some mileage on it and I thought my review of it would be much more comprehensive if I waited until now to publish it rather than a simple first-impression evaluation. Sadly, Kawasaki has discontinued the ‘SF’ model, however the more off-road-oriented KLX250S, which is the original model that the SF was based off of, is still available and it’s essentially the very same bike with different wheels and suspension settings. So if you’re in the market for either model bike, this review should be helpful.
My very first impression of the KLX when it arrived was was that it is a rather large bike for a 250cc-class platform. Somehow it did not seem as large in the showroom, but I was actually pleased by its size – this wasn’t some part-time scoot-around bike; it was a fully-capable road bike that could take me anywhere. I was yet more pleased I decided upon a street-legal machine like this rather than that trail bike I was considering.
I won’t grind you down with all of the KLX’s technical specifications, but some things should be noted for purposes of my final opinions on the 250SF. Both the SF and S models are based on the very same high-tensile steel box-beam perimeter frame, which also cradles the engine underneath and provides two small engine guards at either end. The welds on the frame are pretty clean, and the frame design grants very easy access to all components on the engine. The MX-style bodywork has the same type of finned air shroud for the dual radiators, plus there is a small auxiliary electric fan.
Mechanically, this is a pretty simple bike in modern terms – power comes from a 249cc, liquid cooled single-cylinder dual overhead-cam four-stroke that is fed by a Keihin CVK34 carburetor. The lack of electronic fuel injection does keep the price down, however the Honda CRF250L is fuel injected and has a lower MSRP ($5099 verses $4499 for the Honda). The Japanese version of this bike, known as the D-Tracker, is fuel injected – so why not the U.S. model? Who knows – perhaps we will see fuel injection on the KLX250S in the near future. The KLX250SF and the current S model are 50-state legal, which is no easy feat for a carbeurated engine these days, especially becoming CARB-compliant. The way Kawasaki achieved this was two-fold; the engine is jetted to run extremely lean and there is an added fresh-air injection system that increases the temperature of the exhaust, which is supposed to further burn off any exhaust gases – sort of like a cheap catalytic convertor. The result of this emissions-compliant fuel jetting is very quirky starting and running behavior that I need to discuss. Let me explain…
This setup makes me wish for fuel injection like never before. The KLX bikes are notoriously difficult to start, even when fully warmed up. The situation here is actually a bit strange – the engine starts easily when cold and choked, however if you cut the engine when it is warm and try to restart it right away, you will need to partially choke it or you will be exercising the starter motor more than you should. The trick is to wait a few minutes and the engine will fire right up without using the choke. This could get particularly annoying when making fuel stops, and when I first encountered this odd behavior I was wondering if there was actually something wrong like a stuck carburetor float. Nope, this is normal for the KLX – and it just makes me wish all the more that this bike was fuel injected. Other than this, the little 249cc engine requires an absurdly long time for warmup for an engine this size; usually about 10 minutes.
Somewhat to my dismay, there are no easy way to partially-choke the engine since the choke knob is sprung so it will return to its off position unless fully engaged. So you either fully-choke the engine or not at all; anything in-between requires you to hold the choke knob so it will not spring back to the running position. This would not be much of an annoyance except that starting the engine fully-choked will immediately bring it up to 4000 RPM, which is not a very good way to start a cold engine. That would certainly warm it up quicker, but it’s better to give it a few minutes at lower idle to let the cold oil circulate through the engine before allowing it to rev that high. So I find myself having to hold the choke knob (located on the engine itself) partially out during warm-ups to allow the engine to idle at a lower RPM without stalling.
Something worth mentioning is a peculiar result of the exhaust air-injection system; it increases exhaust temperature so much that on some occasions I noticed the header glowing orange, even at idle! At first I wondered if this was the result of the engine’s extremely-lean jetting, but upon further examination I learned it was caused by the air-injection system doing its job. That kind of thing would not only surprise anybody, but it would alarm people that do not realize it is a normal effect of the emissions device. Kawasaki should think about mentioning that in the owner’s manual.
Once fully warmed up, the thumper runs great and has fantastic low-end power and throttle response. The six-speed transmission felt a bit notchy at first but now that it has been broken-in, it shifts very smoothly and is a joy to use. There is a positive neutral finder that should be helpful to newer riders. The clutch pull feels just right and the combination of a hydraulic dual-piston caliper/300mm pedal-disc brake up front and the rear single-piston caliper/240mm pedal disc gives this bike exceptional stopping power, which I had to take advantage of several times to avoid oblivious drivers.
One thing the 250 is not is quiet – and to me, that’s not a good quality for this particular engine. The stock muffler does little to subdue the engine’s four-stroke characteristic lawnmower-like exhaust tone, and aftermarket slip-ons seem to do little to mitigate this as well; usually just making it louder. Some people may like the way they sound, but to me, all single-cylinder, four-stroke engines tend to sound like lawnmowers, however the exhaust tone tends to become more motorcycle-like as the RPM increases. Fortunately, the Kawasaki engine revs very high, pulling nicely to its 10,500 RPM redline. Low-end power is very good and the SF has no trouble keeping up with frenzied urban traffic.
While cruising at highway speeds, the engine is running comfortably around 5500-6500 RPM with plenty of power to spare. You can quite easily run the KLX on the interstate at 70 MPH with no concerns, and there is very little vibration in the handlebars, nor is the engine overly buzzy. While highway jaunts are handled with relative ease, this bike is really best suited to an urban environment. I’m not saying I wouldn’t use the SF for a daily freeway commute – in fact, I would, but the gearing on this bike really lends itself well to small roads and city riding. Underscoring this point is the KLX’s paltry two-gallon fuel capacity, and although both the S and SF can achieve around 65 MPG, the fuel tank still feels small and there is no fuel gauge. That makes little sense to me on what is supposed to be a fun adventure-bike. There are larger-capacity aftermarket fuel tanks available, though.
One characteristic of this engine is the amount of mechanical noise it makes, especially at low RPM when it produces a knocking-like sound, which is not an engine knock of any sort, but it tends to alarm some new users of this bike. Also, there tends to be quite a bit of intake noise and a pronounced ‘pumping’ sound from that large piston doing its job. All of this is completely normal though, and the KLX engine is reputed to be extremely durable. Also worth noting is that given the 11.0:1 compression ratio of the engine, I would recommend using only premium fuel when possible.
Now for the more important stuff; how does the SF handle? Quite exceptionally all around, in my experience. The suspension is not overly-plush and this bike can handle corners and twisty roads in a manner that makes it even more fun than my ZX-6R in some respects. No, I’m not dreaming – bikes this light are in a class all their own and I do not think there are many bikes out there that could out-corner the SF. The engine provides good power at both low and high RPM and the bike has enough power to keep your ride fun.
Kawasaki lists the SF as 302 pounds, but it feels much lighter on the road. The stock Road Winner tires do their job well, and hard braking will not cause excessive compression in the forks. On the subject of the forks, Kawasaki’s website states that the 43mm inverted-cartridge fork has 16-way compression and rebound adjustments, but I could not find any means of adjustment. The rear UNI-TRAK suspension features 8.1 inches of travel, a remote gas-charged reservoir and has a 16-way adjustment for compression and rebound damping.
Rider position is as you would expect from a bike of this type, which is to say, very comfortable and unencumbered. The LCD instrument cluster is large and the blue backlighting is nice, but I think the tachometer display could be improved; the RPM numbers are quite small and could be difficult to read at a quick glance. Putting that minor issue aside, there are two trip indicators as well as an overheat warning, and the display is easy to read even in direct sunlight. The 33.9-inch seat height is low enough to accommodate most riders without difficulty and rear foot pegs are provided for a passenger. There is a small toolkit that is attached to the rear fender, and even a helmet lock on the side of the bike. General maintenance on the KLX is as easy as it should be on any bike this size. although I wish the swingarm had provisions for spools to set the bike on a stand more easily.
Having spent this much time with the KLX250SF, I find myself still getting excited to ride it – almost like the feeling you get when you ride a new bike. The SF is really that much fun to ride. It’s the kind of bike that you will routinely take out for a ride even if you have no particular place to go and a fantastic bike for both new and experienced riders.
