2018 KAWASAKI KX250F

In 2017, we saw an all-new KX250F hit the floors. It was lighter; more nimble, faster revving. After a big year, you could expect Kawasaki to rest on that one for a while, but it seems the Green Team weren’t done yet.

Words: Broxy Pics: Paul

There was no mistaking the Kawasaki as it was rolled out of the Dr. D van, as its plastics are certainly unique, and not just for their colour. The solid strip of plastic running from the fuel cap to the side plates stands out visually, even though it is completely unnoticeable when you hop on the bike. As well, the green 250F has to be the narrowest 250 of them all – something the engineers worked hard to achieve last year.

There was hardly a single component from the 2016 bike that would fit on the 2017 model. When asked, ‘what did they change?’ the answer is ‘well, basically everything’. With a new frame, engine, intake, air box, swing-arm, radiators, seat, tank, linkage, shock spring, fork spring, and many smaller changes, there really isn’t much of the original left.

The most noticeable change is in the radiator department, where Kawasaki has shaved over three centimetres in the shrouds area between your knees, despite having increased the fuel tank size. It was the closest thing to sitting on a two-stroke that you will get from any of the Japanese manufacturers, aside from rival Yamaha’s YZ.

Kawasaki’s 2018 KX also handles more like a two-stroke. While it may have lost some of its stability, no one was complaining, because it is so much easier to throw around than the previous model. Even the power had become more revvy, to the point where your left foot had to remember how to tap dance again. All of this was well and good, but Kawasaki decided it wanted more traditional four-stroke power for 2018. I was amping to discover the end result.

Less is More

You have to understand the language that manufacturers give you in a bike release. ‘Bold new graphics’ has become a euphemism for ‘Basically the same as last year’, while ‘Optimised settings’ could mean anything. Kawasaki likes the word ‘Revised’, which is how they describe almost everything on the KX from the air intake boot, to the injector angles and cylinder head.

What amuses me is how they used ‘revised’ to describe a change to the compression ratio. Why? Because this year, it is slightly lower than it was in 2017 and in the meantime, everyone else is wanting to increase their compression for more power. What was the company thinking? Reliability over performance? Well, while I don’t know about any reliability problems, obviously, Kawasaki knew what it was doing with the power, because this engine actually has more grunt than it did last year.

As testament to this, Pirini Motorbike Park is a good test of horsepower because of its open layout, and the sandy sections will punish a lack of torque. We also had plenty of slippery sections from recent rain, giving us a very good gauge on performance. What stood out to me from the start, was how linear the power had become. An increase in torque was the most likely answer to why that would be, giving it a feeling of safety. The bike is obviously still only a 250, but the torque almost guarantees that a slip of the clutch is enough to get the motor humming without dropping off the boil.

The trade-off to this extra torque is that I felt the bike struggling to rev out as cleanly as last year. A quick change to the white (aggressive) coupler would probably help, but I didn’t mind. As mentioned earlier, last year’s bike felt more like a two-stroke in how it revved, meaning you rode higher in the rpm range. This seemed to leave the rider dancing on the gears more, whereas this bike is closer to your traditional four-stroke power. Objective achieved Kawasaki, but how exactly did you achieve the change?

For 2018’s KX, we have seen a fatter header pipe, which I assume, helps extract the exhaust gases out faster. By itself, that would make the bike louder, except that the header pipe is now 30mm longer. The result is a bike which is actually quieter than the previous year’s model, something I really appreciate because Kawasaki’s bikes are typically on the louder side. Now the KX plays a more enjoyable melody and the neighbours shouldn’t get quite as annoyed, either.

Other changes include a ‘revised’ intake duct and a shorter intake funnel, along with many ‘new’ things. In this category, is a new intake camshaft, new fuel pump and new cylinder head design. There is also a new throttle body with a less vertical injector mounting angle. This works in tandem with the other injector closer to the air box, which has set this bike apart since 2012.

The normal injector is tasked with giving low to mid-range power, but the higher the rpm and harder you turn the throttle, the more it switches to the second injector, which gives the fuel time to break into smaller drops and cool down more. This technology is fine tuned to the point where how it behaves, depends on whether you are in a low gear like first or second, or in one of the higher gears. This is not new, but very cool nonetheless.

On the Pro Circuit

Let’s just take a moment to appreciate the weight of all these changes. The list of changes to the 2018 KX250F’s powerplant is almost like Kawasaki giving your new motor to Mitch Payton for an overhaul even before you receive it and not charging you any extra for the privilege. Changes to the head no doubt help the flow, while increased pressure is the result of the new fuel pump. Even the intake valve timing has been advanced. This is all in addition to new ECU settings which still work with the couplers to allow for a quick and easy change of maps.

Something we didn’t mention about the exhaust is the resonating chamber, which was only available on aftermarket pipes in years gone by. Kawasaki seems to be doing all it can to help its riders, and while the KX250F still won’t top the horsepower charts in its class, it will make you accelerate quicker with less effort. What’s not to like?

The other major area that Kawasaki wanted to fine-tune after last year’s mammoth effort, is the suspension. One of the few bikes that avoided the air fork craze, the KX250F has stuck to Showa 48mm Separate Function Front Forks, a name referring to having a spring in one fork and all the shims for rebound and compression dampening in the other. For 2017, the spring weight was increased, but for 2018 it was dialled back down again. The lighter spring seems to work better because it enables an increase in preload, an adjustment rarely seen on a fork. From there, the compression and rebound shims have been changed in the other fork. It sounds like there was a focus on suspension under load, especially through braking bumps. I found the forks very friendly under braking, and I was giving them a hard time. This bike comes standard with a massive 270mm front disc, meaning you can load the front as much as you like with just one finger.

As is usual for Kawasaki, there is a ‘bling’ coating on the fork tubes, obviously in black to match the fork guards and wheel rims. What is less obvious is the ‘self-lubricating Kashima coating’ on the inner shock body. It apparently improves wear resistance and shock action, which Kawasaki aimed to improve with more valving changes. Interpreting the technical language, it sounds like they sped up the rebound dampening.

Kawasaki claim that the new shims improve the ride feel, traction and rear wheel feedback. Personally, I prefer to avoid those traits for the sake of a more forgiving ride. A few laps on this bike proved to me that the KXF250 really did need those changes, because it was now very settled, even over some nasty acceleration bumps. This bike feels like it has embraced the fact that it is not a 450 and seems to get the most out of its lighter weight – which leads on to the biggest thing I noticed about this wonderful machine.

Float Like A Butterfly

The craziest thing about this bike is its manoeuvrability. I really don’t think you can ride this bike without appreciating how easy it is to move around. For years, Kawasaki’s bikes have felt narrow between the legs and easy to move in the air. Since the big changes last year, that feeling has jumped another notch. A flat seat probably contributes, making it easy to move forward and back. Having that narrow feel through the radiator shrouds totally invites you to sit forward for the turns, yet it is a feeling akin to it having a short wheel-base which really stands out.

A quick turning bike is not usually the most stable, which is where the faster sections at Pirini really work as a test. Sure, it may be less stable than some bikes at high speed, but not so much as to make it a liability – not even close. Then you get back to the tight stuff where it shines once again. This is the balance I think Kawasaki has always been looking for. With a bike that is easy to move, you quickly become friends. It is easier to spot a line and go for it. I must admit to full confidence at hitting some lines that I probably shouldn’t have. Then if the line I was in became difficult, I didn’t have trouble changing to something different.

In the same sense, the way the bike feels in the air is distinct enough that I can’t just pass it off as being in my head. Turn the handlebars and the gyroscopic effect of the front wheel is enough to move the rest of the bike into the same plane. Turn the front wheel back in line with the track and the bike will soon follow. This is what I noticed most aboard this bike, and while I can’t explain exactly why, it is a lot of fun. But, there is one last thing which absolutely needs a solid mention, and that is how this bike will get on down the start straight.

I wanted to give it a solid test because of how much the power of this bike has changed. After all, from reading the promotional material on the KX, you would be disappointed if it didn’t give you a better run down the start line. So, you are sitting on the line in neutral. With the bike idling, find the big red button just to the left of the handlebar pad. By pushing and holding that button for a second or two, you have engaged what they call ‘Launch Control’. If your heart rate doesn’t bump up just a notch when you see the flashing orange light firing like a machine gun, then you are just not in the moment enough.

Boosting off the line in second gear, I found it hard to break loose and spin the rear tyre, quite like I would like when the launch control is engaged. But then, I often can’t spin the rear wheel as I would like to with launch control off, either! Without loads of practice on lots of different soil types and conditions, getting the perfect start without the launch control is something of a lottery. What I can tell you is, that a slightly messed up start WITHOUT the launch control engaged, is almost always worse than if you were using it.

So how does the 2018 hold up off the start? Like I said, I struggled to get it spinning, but I could definitely feel the torque in action. Using the launch control somehow amplified that feeling of torque, even though it probably shouldn’t have. There is a big difference between the bike just sounding like it is going good, and actually pulling. Fortunately for Kawasaki, this was definitely the latter – it pulled hard!

Looking back over the changes for 2018, it is as if Kawasaki felt it had gone too far in some areas last year and not enough in others, so they just got stuck into it. I can’t imagine how many hours of testing this kind of development would take, but it is certainly not in vain. This bike is an improvement, enough to keep the Kawasaki faithful happy for at least another year or two.

2018 Kawasaki KX250F Specifications

Price: $12,695 + ORC

Type                                            Liquid-cooled, 4-stroke, single cylinder, DOHC, 4-valve

Engine Displacement              249cc

Bore x Stroke                            77.0 x 53.6mm

Compression Ratio                 13.4:1

Carburation                              Fuel injection: 43mm x 1 with dual injection

Fuel Tank Capacity                 6.4 litres

Transmission Type                 5 speed return

Final Drive                               Chain

Frame Type                             Aluminium, perimeter

Dimensions (LxWxH)           2172 x 825 x 1270mm

Wheelbase                               1478mm

Trail                                         123mm

Seat Height                            945mm

Kerb Weight                          104.7kg

Suspension Front                 48mm upside down telescopic Separate Function Fork (SFF)

Suspension Rear                   New Uni-Trak

Tyres Front                            80/100-21 51M

Tyres Rear                              100/90-19 57m

Brakes Front                          Single semi-floating 270mm petal disc, dual piston caliper

Brakes Rear                           Single 240mm petal disc