September is a pretty exciting time of year in the motocross world, by now the specs have been released on most new models and at least one of the big manufacturers has claimed the Early Bird status and landed their new offerings in dealerships Australia wide.
This year Kawasaki has set the pace, with the early release of the KX250F, and to make things even more exciting, the 2017 model is an all-new machine from the wheels up.
Lighter, faster, slimmer
… is the tagline Kawasaki is using to promote its new 250, and sure, it may seem obvious making the bike lighter and faster will improve its overall performance but if you take a look at the engineering behind the new KX it’s pretty clear Kawasaki didn’t just bolt on a few new fast parts and assign the KX250F to the latest fad diet program.
Beginning with the faster updates to the KX250F, the entire engine intake system has been revised.
The engine has been straightened up and now sits seven degrees more upright, with the throttle body, dual fuel-injection and air filter positions raised to allow for a straighter, and more downdraft-shaped intake.
The dual fuel-injection system has its changes as well, with a new downstream (closest to the engine) injector, featuring more holes and a finer, wider spray.
This is said to have increased power in the low-mid RPM and added throttle response.
The upstream (further from the engine) injector remains unchanged.
The cylinder offset has been changed, and is now 3mm further forward, with a new honing technique used called plateau honing, which leaves a smoother surface finish on the bore of the cylinder.
Both of these improvements are aimed at reducing mechanical loss, providing increased efficiency and power output.
A new ‘race replica’ piston replaces the previous design, which features a molybdenum coating instead of tin plating to reduce friction.
Further updates to the piston include design changes to the bridged box bottom and pin position to increase strength while shaving weight at the same time.
The crank design changes slightly from the 2016 design too, with a new web design shape increasing the balance factor to around 70 per cent, which is claimed to be on par with the factory race engines.
The new crank contributes to reduced engine vibration and smoother power at higher RPM.
Making the KX250F lighter and slimmer was just as in-depth for Kawasaki’s engineers, with a complete chassis re-design being in order.
The steering stem shape, shock mounting tower design and swingarm mounting area have all been completely revised to increase rigidity and give the chassis a 6mm slimmer profile.
The front ‘downtube’ section of the chassis is now a made from a forged section at the front and a cast section at the rear where previously it was a single extruded piece design.
All components are still aluminium, however the manufacturing process for each piece changes the outcome once the chassis is fully assembled, making the overall design stiffer and lighter.
The swingarm from the KX450F comes directly across to the 250F with no changes at all, its a more rigid aluminium design, with the new construction saving almost 200 grams.
New bodywork on the KX not only gives a fresh new look with stylish in-mould graphics, a first for Kawasaki, but the redesigned seat and 6.4L fuel tank give a slimmer, flatter riding position.
The radiators are re-positioned lower and are 20mm narrower to allow even more room for the rider to move around on the bike.
To match the updated chassis, new suspension settings have been added at both ends.
The Showa Single Function fork receives a firmer spring rate and new valving, while the Showa rear-end receives a softer spring rate with new valving.
This means less ‘pitching’ from the back-end while under load, and increased stability at speed.
Remaining unchanged on the KX250F are the Renthal handlebars, adjustable handlebar position mounts, adjustable footpeg height mounts, Black wheels, and oversize 270mm front disc.
The Ride
Things weren’t looking so great however, as shortly after we arrived the heavens opened and dumped torrential rain on the circuit.
In a stroke of genius, the Ride Park crew worked tirelessly during the night and trucked an unbelievable amount of sand into the carpark and built a temporary track just so us media mugs could still have a spin on the KX250F.
The track was short and quite sandy, which if you check out our short video you will see.
So while conditions weren’t ideal, we still managed to spend a solid day upon the KX250F and came away impressed with what the 2017 model had to offer.
Faster is the first thing I noticed on the track, the free-revving feel to the engine is still there from previous years but the low- and mid-range power comes on much stronger.
Gear changes aren’t as critical thanks to the extra punch, and if you’re in the tight stuff you can lug the KX around a bit easier at low revs.
In the sand the KX blasted through deep turns easily, maintaining speed and transferring plenty of power to the ground.
Through the uphill rollers we were able to stretch the Kawasaki a bit more where the top-end power is as strong as ever.
At no point did we find the green machine signing off early or revving hard while going nowhere.
The clutch action works great with an easy pull, and the standard gearing was just fine around the short test track.
The overall feel of the engine is much smoother and more refined thanks to many of the upper engine changes, and even though there are no apparent gearbox changes, gear shifting appeared to be a bit easier and not as ‘clunky’ as we have experienced in the past.
The new bodywork and chassis certainly gives off a slimmer profile to the Kawasaki, and anyone jumping off a 2016 model will notice this immediately.
The general body positioning is much more aggressive and ‘on-top’ of the bike.
The flatter seat and narrower shrouds allow for much more body movement, making it easier to shift your weight through turns and towards the rear through the rough stuff.
The narrower profile gives a more nimble feel as you flick the bike around the track, and dart from one line to the next.
The weight savings didn’t appear to be as evident as the narrower profile, but that’s not to say the KX250F wasn’t light and agile already.
As far as handling and suspension goes, the short sandy test loop didn’t offer much variety or a mix of conditions that we would normally ride, so it was difficult to come up with a solid opinion.
That being said, the Kawasaki was predictable in all areas of the track during the day and never once threw us off guard.
Through turns the KX held its line well and was smooth and stable under acceleration.
Due to the soft sand we decided to stiffen up the Kawasaki on the compression, at both front and rear of the bike which worked well to hold the bike up and give less of a diving feel through the deep sandy corners.
Through the sand whoops the KX was stable and maintained straight line stability without bottoming or deflecting in the rear.
The overall feel was great around the sand loop.
Due to the conditions, it’s can’t be said definitely, but it can be said with a well-educated certainty the KX would handle just as well in more typical, drier conditions.
Verdict
The 2017 KX250F is an impressive machine, the engine improvements make sure the KX remains competitive with the best bikes in the 250cc class, while the chassis and bodywork updates make the Kawasaki a much easier bike to ride.
The Showa suspension is a proven package from years gone by and with quality components like Renthal Handlebars, moulded graphics, Dunlop MX3S Tyres the 2017 KX250F is ready to ride, straight off the dealership floor.
