2013 Kawasaki KXF’s – Tested

The new ‘green meanies’ just got leaner! Kawasaki continue to march forward as their success on the race track filters down on to the production models for 2013.

You don’t have to look very hard to see that Kawasaki have really been putting some major effort into their adult motocross range over the past few years. They have been incredibly successful in America over that time, particularly with Ryan Villopoto on the 2012 KX450F dominating the Supercross, no doubt he would’ve also started the outdoor season in the US as favourite if it wasn’t for injury. In Europe the likes of Gautier Paulin, Christophe Pourcel and Tommy Searle have all been winning races regularly in the World Championship and whilst you can argue that it’s the incredible talent of those riders bringing success they still need the tools to get the job done. Kawasaki are working incredibly hard on motocross right now and the rewards are filtering through on the track but more importantly they are also coming to the consumer, which of course is what it’s all about.

The 2013 KXF’s reap the reward of that increased effort put into racing and development with a whole host of refinements; some big, some small but they all work together well to yet again improve two already very good motorcycles. Both machines are now slimmer at key contact points and have a flatter seat and a easier, user friendly power delivery but the most significant and noticeable difference in performance in particular is to the pneumatic front forks on the new KX450F, but before we get to that lets get into the finer detail of each bike.

KX250F

The previous 2012 model made a big step forward with the dual injection EFI and vastly improved the bike so it came as no surprise that Kawasaki have not made any radical changes to it. What they’ve done is take that incredible response and strong torque from the motor and made it easier to ride and more user friendly for the average rider at the track. Just like the 2012 KX450F the new KX250F now comes with the DFI Setting Data Selection making it quick and simple to adjust the power simply by replacing the coupler that’s easily accessible on the headstock. The new intake porting and more direct flow from the airbox make what was an already razor sharp response even sharper which is quite amazing considering how crisp it was before. The track conditions were perfect to test the adjustability given to the rider with the DFI coupler, with some parts well watered and heavy going and other areas hard pack and slick. The stock ‘green’ coupler was ideal for the circuit as it’s middle ground. When the more hard hitting ‘white’ coupler was on the bike it definitely gave the bike more grunt at the bottom to middle to cut through the heavier soil but it was a lot harder to control the power being delivered to the rear wheel on the hard pack. A quick 30 second pit stop to change the coupler over to the smoother ‘black’ coupler and ‘hey presto’ it was the complete reverse, just like that it was so much easier to get the power to the ground on the shiny stuff but the bike felt that little bit more sluggish through the heavier soil. It’s a system that definitely works and although it’s not as noticeable as it is on the KX450F it’s a masterstroke really as it makes life so much easier. Add to that a stronger motor than previously and it makes the 2013 KX250F a great bike to ride.

Kawasaki say the motor is now higher revving and they can feel confident in that statement because it is, yet it hasn’t really lost any of it’s bottom grunt, and all this while making the bike quieter with a new exhaust system (the bark of the KX450F has also been tamed so both bikes meet the European 112 dB ruling). Kawasaki have achieved the extra RPM’s by introducing a new, shorter cylinder by just 0.1mm. It doesn’t sound a lot but what that has done is increase the compression from 13:5:1 to 13:8:1 and with a new intake cam, 30cc shorter exhaust pipe, revised piston profile and ECU it means you can hold those gears a little bit longer. So not only does it make the bike faster at the top end it also give the bike more scope to suit a particular riders style. Make no bones about it, the KX250F has a very strong motor from top to bottom, put it this way, with the evolution of the last few years and now these new upgrades this engine has come along way in a short period of time and for the average Joe (which every manufacture aims to please) it’s hard to pick holes in the performance of this motor.

As good as it is having a great motor it’s all lost if the chassis and suspension let the side down, thankfully neither do. The new frame is 4mm narrower across the point of the main down tubes where the riders knee grip the frame (2mm on each side) and with the flatter seat and lower, smaller fuel tank it’s an absolute breeze to move up and down the bike and shift your weight about. It really does inspire confidence through turns and into the face of jumps as you put your weight anywhere you want without too much effort. It’s easy to feel part of this bike rather than feeling like you’re some kind of dead weight it’s pulling around.

The Showa SFF Type 2 forks have also received an upgrade with larger 48mm diameter inner tubes that give a little more rigidity and stability on the front end and they continue to work well. The only criticism is that maybe they come a little soft on the standard settings, as always the adjustment is there but depending on your level it might raise concerns. If you’re a pro or good standard club rider or packing pounds that you shouldn’t be you may find yourself on the limit of adjustment and have to consider a stiffer spring or changing the oil levels. The longer stroke on the rear suspension compliments the front end well making the bike well balanced but like the fork, the faster you go as your confidence grows on this bike then you may well have to look at making changes to both the suspension units beyond the adjustments available to you.

KX450F

From a user friendly point of view the 2102 KX450F was definitely a winner with the adjustability of the ergonomics and easy to change mapping couplers, so how have Kawasaki improved on that? Well just like the KX250F they’ve made a higher revving user friendly bike. The KX450F also has a revised piston by lowering the crown by 0.2mm, the intake cams have a reduced lift of 0.4mm. Add those changes to the wedge shaped crank web which according to Kawasaki at close to 60% the balance factor is on par with Villopoto’s factory machine and it’s no wonder the 2013 KX450F has less vibration and a smoother, stronger power delivery and yet it’s even more responsive from the bottom.

The 2013 KX450F is definitely the smoothest model they have made so far and arguably the quickest, but it’s the latter that’s not so instantly noticeable. As a rider it’s easy to believe you’ve ridden a quicker KX450F in the past (if of course you have) but the thing is the power delivery is so smooth and easy you don’t feel like you’re going fast, it’s in the lap times that you realize how fast the 2013 KX450F is.

Add to that the launch control mode that Kawasaki introduced for 2012 and you may well find your chances of running near the front of the pack from the start to finish are better on this bike. The launch control makes such an incredible difference in getting you out of the gate and putting you in contention for a holeshot and now with an even sharper response and a harder torque it rips from a standing start to the braking zone with ease as you flick through a smooth gearbox with confidence. Anywhere on the track it feels like you have this disposable power on tab and as soon as you twist the throttle grip you’re hooking up and going forward with hardly any wheel spin, almost like the bike is automatic. You could argue ‘where’s the fun in that’ and maybe with less power it’s a more than justifiable argument but with the 2013 KX450F it really feels like there’s nothing you can’t do on the track and the only thing holding you back is your own ability and quite possibly fear of pushing the boundaries of that ability and getting hurt.

Like it’s little brother the new 450 also has the narrower frame, flatter seat and lower fuel tank but it benefits more by having the 4-way adjustable handlebar position and 2-way footpeg adjustment that Kawasaki introduced last year. If you can’t find a set up that gets somewhere close to perfect on this bike in stock trim then the chances are you’re too anal for your own good, especially as Kawasaki continue to offer the 1mm longer suspension tie rod that lowers the seat height by 4mm at the centre of the seat. Chances are you’ll want to change the handlebar bend to suit regardless but other than that you can get this bike pretty close to exactly how you want it, certainly without spending money you may have to on other manufacture models.

So with a brilliant motor and adjustable ergonomics to suit everyone there’s some emphasis on the suspension to keep the good vibe going and it does so with great effect with the introduction of the new KYB PSF (Pneumatic Spring Fork). As regards of pioneering engineering the PSF fork isn’t something completely new and has been seen kicking around in Mountain Biking in some shape or form but regards of MX it’s a bold move by Kawasaki and KYB and it’s move that looks to be justified. From the first moment you sit on the 2013 KX450F and push the forks down you can feel the difference. Where on other forks there’s that initial ‘sticking’, if only for a fraction of a second, before the stroke starts to work smoothly with the new PSF fork there doesn’t appear to be any early resistance at all. They’re so plush and responsive they instantly inspire confidence and that’s before you even pull the kickstart out and start the bike. Out on the track the difference is equally as noticeable. When over jumping a large tabletop and flat landing the forks just soaked up the impact. Where usually you get all the initial impact through your forearms and the shockwaves go up through your shoulders before the forks soak up the rest of the impact the new forks make it feel like you’re collapsing onto a comfortable bed after a long day, if not quite with the same satisfaction, then certainly not far away from it. As if that isn’t enough the forks weigh 750g less, have far easier adjustment and a wider setting range and because there’s no traditional fork springs the internals allow the fork tubes to be much larger, going from 24mm to 32mm, the result meaning there’s more bottoming resistance and stable damping especially when changing from rebound to compression. Now you can even adjust your forks at home with a bicycle pump without having to get into a mess or a tizz changing the oil. By simply changing the PSF fork pressures you have the same range of settings offered by optional springs on a standard fork, which again only adds to the user-friendly adjustability of the KX450F.

The rear shock also has the mounts below the swingarm that allow a longer rear stroke and allows more precise tuning and adjustment. Just like the KX250F the rear shock compliments the forks exceptional well and the balance and feel really is a pleasure. Unlike the KX250F however the KX450F is nearer the mark with the stock settings and not as soft as it’s little brother, basically it’s beefier and can withstand more aggression thrown from a heavier or faster rider, or both!

Both models have a new longer handlebar grip with a new pattern and softer material that aren’t exactly a deal clincher in wanting to buy the bike but nonetheless are a nice touch and improvement. Both models benefit from a new push rod front brake master cylinder, which definitely gives a lighter feel under hard braking. Other small changes (amongst others) like a more durable chain guide and new front mudguard just add further to the plus points on both models and the new styling of the plastics are another positive step forward, not only for the look but the ergonomics. The KX250F in particular is a much better looking and feeling bike because of them.

All said and done it’s a stellar effort by Kawasaki yet again as they continue to drive forward. They’ve produced two motorcycles that really do cater for all levels of riders on every level necessary. If these bikes are the knock on effect of racing and development, which they are, then the results speak for themselves. They say ‘proof is in the pudding’, if that’s so then in this case the pudding definitely leaves a sweet taste in your mouth.

2013 KX250F SPECS

ENGINE
Engine type Liquid-cooled, 4-stroke Single
Displacement 249 cm³
Bore x stroke 77.0 x 53.6 mm
Compression ratio 13.8:1
Valve/Induction system DOHC, 4 valves
Fuel system Fuel injection: ø43 mm x 1 (Keihin) with dual injection
Ignition Digital DC-CDI
Starting Primary kick
Lubrication Forced lubrication, semi-dry sump
DRIVETRAIN
Transmission 5-speed, return
Final Drive Chain
Primary reduction ratio 3.350 (67/20)
Gear ratios: 1st 2.142 (30/14)
Gear ratios: 2nd 1.750 (28/16)
Gear ratios: 3rd 1.444 (26/18)
Gear ratios: 4th 1.235 (21/17)
Gear ratios: 5th 1.045 (23/22)
Final reduction ratio 3.846 (50/13)
Clutch Wet multi-disc, manual
FRAME
Frame type Perimeter, aluminium
Wheel travel, front 315 mm
Wheel travel, rear 310 mm
Tyre, front 80/100-21 51M
Tyre, rear 100/90-19 57M
Rake/Trail 28.7° / 126.4 mm
Steering angle, left / right 42° / 42°

SUSPENSION
Suspension, front Type: 48 mm upside-down telescopic
Separate Function front Fork (SFF) Type 2
Compression damping: 22-way
Rebound damping: 20-way
Spring preload: 40-way
Suspension, rear Type: New Uni-Trak
Compression damping: 19-way (low-speed),
4-turns (high-speed)
Rebound damping: 22-way
Spring preload: Fully adjustable
BRAKES
Brakes, front Type: Single semi-floating 250 mm petal disc
Caliper: Dual-piston
Brakes, rear Type: Single 240 mm petal disc
Caliper: Single-piston
DIMENSIONS
Dimensions (L x W x H) 2,170 mm x 820 mm x 1,270 mm
Wheelbase 1,475 mm
Ground Clearance 330 mm
Seat height 945 mm
Curb Mass 106.2 kg
Fuel capacity 6.1 litres

2013 KX450F SPECS

ENGINE
Engine type Liquid-cooled, 4-stroke Single
Displacement 449 cm³
Bore x stroke 96.0 x 62.1 mm
Compression ratio 12.5:1
Valve/Induction system DOHC, 4 valves
Fuel system Fuel injection: ø43 mm x 1 (Keihin)
Ignition Digital DC-CDI
Starting Primary kick
Lubrication Forced lubrication, semi-dry sump
DRIVETRAIN
Transmission 5-speed, return
Final Drive Chain
Primary reduction ratio 2.727 (60/22)
Gear ratios: 1st 1.750 (28/16)
Gear ratios: 2nd 1.412 (24/17)
Gear ratios: 3rd 1.188 (19/16)
Gear ratios: 4th 1.000 (19/19)
Gear ratios: 5th 0.875 (21/24)
Final reduction ratio 3.846 (50/13)
Clutch Wet multi-disc, manual
FRAME
Frame type Perimeter, aluminium
Wheel travel, front 314 mm
Wheel travel, rear 315 mm
Tyre, front 80/100-21 51M
Tyre, rear 120/80-19 63M
Rake/Trail 26.9° / 113 mm
Steering angle, left / right 42° / 42°

SUSPENSION
Suspension, front Type: 48 mm upside-down AOS-type
Pneumatic Spring Fork (PSF)
Compression damping: 22-way
Rebound damping: 20-way
Suspension, rear Type: New Uni-Trak
Compression damping: 22-way (low-speed), 2-turns or more
(high-speed)
Rebound damping: 33-way
Spring preload: Fully adjustable
BRAKES
Brakes, front Type: Single rigid-mounted 250 mm petal disc
Caliper: Dual-piston
Brakes, rear Type: Single 240 mm petal disc
Caliper: Single-piston
DIMENSIONS
Dimensions (L x W x H) 2,180 mm x 820 mm x 1,275 mm
Wheelbase 1,480 mm
Ground Clearance 330 mm
Seat height 955 mm
Curb Mass 112,5 kg
Fuel capacity 6,2 litres

MX Vice Editor || 25

Leave a Reply

Your email address will not be published. Required fields are marked *