Green Party!
Published: 09th November 2006
Author: Words by Tony Marshall and Sutty Photos by rayarcher.com
Take four new Kawasakis, two testers, one photographer, an awesome location and a rather lovely buffet and you've got one hell of a green gathering going on...
2006 has been a great year for Kawasaki as the green team's riders have secured both supercross and motocross world championship wins as well as countless domestic titles right around the globe. And with four bikes in the 2007 Kawasaki motocross range there should be something to suit everyone from novice to pro which is something we all can celebrate.
The two two-strokes in the full-size range - that's the KX125 and KX250 - have only received slight visual changes for next year. New graphics and 'factory' brown hubs and triple clamps are the only 'improvements' made to the green screamers but an all-new lower price tag, the lesser running costs and the inclusion of an open class at the oh-so popular two-smoke only DEP Challenge series should help a few of these bad boys shift from showroom floors.
With the two-stroke models left feeling miffed at being mostly ignored and undeveloped for '07 the same can't be said for the flagships of the Kawasaki range - the 250 and 450F models.
The KX250F has been the MX2/lites/125 class bike to beat in '06 with major victories coming from Christophe Pourcel in Europe with Grant Langston and Ryan Villopoto doing a clean sweep in the States. While it's fair to say that the riders' skills played a major part in that success it's arguable that if the '06 KXF hadn't offered such a stable platform to build success on fewer titles would have headed Kawasaki's way.
And rather than just rest on their laurels for 2007, Kawasaki's top-techs have been looking at ways to improve their 250F - revisions to the frame, suspension and motor prove they're serious about success.
It's the power plant that has come in for most of the modification work. Polished intake ports and ultra-light intake valves should help improve intake efficiency while a revised piston and ring also improve power while updated jetting settings and an all-new ignition curve do their bit to make the KXF a ripper!
Down in the gearbox new thicker gears help improve the box's durability and there's also a new shifter drum and revised ratchet to keep shifts silky smooth.
The 450F also gets gear box mods which make the new bike five-speed rather than the four it was released with in '06.
The valve timing has also been modified to increase low-RPM torque while newly shaped intake ports are claimed to increase throttle response - in theory these mods along with some carb tweaks should make the four-fiddy a ripper!
One of the most noticeable improvements to next year's 450 - besides the bold new graphics - are the diamond-like-carbon (DLC) coated fork tubes that are black in colour - these are possibly the trickest looking stock forks ever seen on a Japanese manufactured bike.
But as sweet as these bikes seem on paper the proof of any pudding is in the eating so we let little Tony tuck in...
Out on the track the '07 Kawasaki 250F has all the pulling power you'd need. It has similar feel to this year's motor but more responsive and with excellent acceleration.
The bike has a stronger bottom-end to mid-range pull for faster acceleration from the turns. The mid to top range power doesn't feel too much stronger but the overall spread feels a bit wider than the '06.
I tried some starts and found second gear worked really well with a smooth drop of the clutch - the power didn't hesitate and it literally just goes and changes gear smoothly with the gas wide open.
With the track being quite greasy and boggy in places you needed plenty of throttle control to get round fast. The motor helps here by being strong and tractable, driving out of the tacky deep muddy turns. This makes for easy riding in these conditions - it just hooks up real easily.
The jetting was sweet and the bike didn't miss a beat throughout the test.
The chassis hasn't had load of changes made to it either but the few changes there are help make the bike loads of fun to ride and it felt really stable on the track. With the track being a bit on the sticky side you had to treat it with some respect.
The front end on this bike is so stable coming into the turns it felt like I couldn't do a thing wrong. Instead of trying to avoid the ruts in turns I was looking for them and didn't feel the bike wanting to ride out of the top of them leaving the rear wheel being dragged behind.
The rear shock feels spot on - it works really well with the front forks and it's so balanced on landings and handles like a dream on the straights. Coming into the turns I never felt the rear move or kick me about under braking.
I didn't feel the brakes had any major improvements on the performance but then again I never felt like they've ever needed them either.
I'm impressed with the 450F. Oddly enough it's the motor that got me the most excited. This motor isn't just fast on the top - it makes power all of the way through the range and there wasn't a single time on any part of the track that I felt I needed more, even in some of the deep tacky turns.
The track was a bit on the wet side in places and that's where the four-stroke's come to there biggest strengths - just letting the motor lay plenty of traction. Admittedly all 450s have plenty of power and torque but the KX still manages to keep this bike more rideable as this is something I do struggle with.
As strange as this may sound the increase in power actually made the bike easier to ride. The spread of power is awesomely long so you can ride this bike in the lower rpm without affecting the acceleration as and when it is needed.
Just play around on tick over this thing is always ready to light up with the power going straight to the rear wheel with none to waste - pure power to the ground.
With the '06 running a four-speed box and the Kawasaki factory changing to a five-speed box for '07. I felt that this was a bigger advantage although I only used second, third and fourth gears which pretty much makes it a three speed box. I never felt like I needed to anything more on the track.
Again like the 250F the 450's jetting was sweet as a nut - there was nowhere in the power range that needed attention. It was just spot on.
As far as the suspension goes I was pleased. The front end is very stable. The KX's rear end felt better than on the '06 but it was a bit on the harsh side. It did get a little better at the end of the day with the bike getting more track time. This bike is wicked - it turns well, it's light and it hooks up.
Moving on to the two-strokes, the 125 - as everybody knows - is a bike which has always been my favourite and the first which I try to throw my leg over for a bit of fun but this was not the case on today.
I put more track time in on the 250 as I got as much fun out of this motor as I would normally get out of a 125. There are certain parts of the track where the four-stroke has a massage advantage but the two-strokes are where my heart lies.
I think that the KX250 is one of the easiest 250 two-strokes to ride on the market and doesn't deliver silly aggressive power like most - it's just great useable power.
specifications
KX125
Capacity: 124cc
Bore and stroke: 54mm x 54.5mm
Transmission: Six-speed
Carburettor: Mikuni TMX38X
Front suspension: Kayaba 48mm USD (300mm travel)
Rear suspension: Kayaba (310mm travel)
Front brake: 250mm disc
Rear brake: 240mm disc
Wheelbase: 1470mm
Seat height: 945mm
Dry weight: 87kg
specifications
KX250
Capacity: 249cc
Bore and stroke: 66.4mm x 72mm
Transmission: Five-speed
Carburettor: Keihin PWK38S
Front suspension: Kayaba USD (300mm travel)
Rear suspension: Kayaba (310mm travel)
Front brake: 250mm disc
Rear brake: 240mm disc
Wheelbase: 1480mm
Seat height: 965mm
Dry weight: 97kg
specifications
KX250F
Capacity: 249cc
Bore and stroke: 77mm x 53.6mm
Transmission: Five-speed
Carburettor: Keihin FCR37
Front suspension: Kayaba USD (315mm travel)
Rear suspension: Kayaba (310mm travel)
Front brake: 250mm disc
Rear brake: 240mm disc
Wheelbase: 1469mm
Seat height: 955mm
Dry weight: 92.5kg
specifications
KX450F
Capacity: 449cc
Bore and stroke: 96mm x 62.1mm
Transmission: Five-speed
Carburettor: Keihin FCR40
Front suspension: Kayaba USD (315mm travel)
Rear suspension: Kayaba (315mm travel)
Front brake: 250mm disc
Rear brake: 240mm disc
Wheelbase: 1485mm
Seat height: 965mm
Dry weight: 99.8kg
Tanky tastes...
Four green-meanies gobbled up!
With an awesome track and four flipping great bikes to test out I was salivating like a rabid dog on steroids as I arrived at the fantastic Tonymoto practice facility after a long drive down from t'North.
With minimal changes made to either two-strokes I figured I'd try these first and save the best - that's the four-poppers - until later.
Kawasaki claim the 250 two-stroke is unchanged bar fresh-coloured hubs and clamps and those sweet new graphics. But that has to be bull! For the first time in a few years the two-fiddy doesn't sound like it's gonna detonate itself to bits when you put the motor under any kind of load which is, quite frankly, very pleasing.
In my opinion the 250 is undergeared and from past experience I've found gearing up the KX really brings the motor alive on a bike that's already very easy and enjoyable to ride without too much modification.
Even though I'm about four stone heavier than your average 125 two-popper pilot I still found the KX125 a whole heap of fun to ride. The motor runs sweet, the suspension is good - although a little soft - and like it's bigger brother, the 250, it's very enjoyable to be in control of. For anyone planning to do the DEP challenge or someone who wants a woods-weapon that's ideal for enduro or hare scramble usage the KXs would be a great choice.
The 250 four-stroke is also a lot of fun to ride although I'd choose to add an extra tooth to the rear sprocket as I found myself stuck between gears on a regular basis either bouncing off the rev-limiter or labouring the motor. I'm sure it would be fine for most 250F riders though, it's just I'm a wee bit heavier than your average MX2 racer.
The suspension on the 250F is good - even for my weight - and the machine handled impeccably all day. Likewise, brake performance and shifting were flawless as was the general running of the bike.
While the 250F is good the 450F is awesome. The 450F was a new bike in the Kawasaki range for '06 and after spending a small amount of time on one earlier in the year I was not impressed. The '07 however is a much improved bike and Kawasaki have totally changed the way I feel about their 450F.
The motor in this thing is frickin' awesome and there's so much grunt you can keep it up the box and carry plenty of speed around even the tightest of turns. In fact the power is so plentiful it helps what's a big bike feel light, nimble and very maneuverable. I felt I could use the power to keep myself out of trouble rather than get myself in it like some manufacturer's 450s seem hell-bent on doing.
The suspension on the '07 feels much more balanced - I felt the zero-sixer sat higher in the rear from stock - and handles well.
To sum up the 450F I'd have to say it doesn't feel like a big open-class bike at all - more like a super-charged 250F. For me at least it's the one bike from the range I truly feel I could pick up from a dealership, slap some numbers on and go race tomorrow.