Kawasaki '636' ZX-6R

"There ain't no substitute for cubic inches." At least that's the mantra Kawasaki appears to be chanting with its re-vamped ZX-6R, the bike that contravenes the 'rules' by creating its own class with an oddball 636cc capacity - a sort of 'super' middleweight.

The move to the 636 designation has means that the machine is inelegible for Supersport racing at any level because it breaks the 600cc capacity limit for four-cylinder machines.

I must admit that when I first got wind of the new model's engine capacity, and its subsequent exile from racing, I was a little mystified as to Kawasaki's motivation for such a move.

Could 37cc really make that much difference? Enough to possibly jeopardise the ZX-6R's formidable reputation on the racetrack (the ZX-6R has won three Aussie Supersport titles since the championship began in 1994, not to mention the world title in 2001)?

Kawasaki thinks so. It reasons that only a small percentage of ZX-6Rs become racebikes, and the average road rider would welcome the benefits of the extra 36cc - namely, more mid-range power and torque - as they go about their commuting, scratching or sportstouring business.

Besides, Andrew Pitt proved beyond doubt that the 2001 jobbie is still a good thing on a racetrack by winning the World Supersport race at Phillip Island recently. So after all the hype over the wacky capacity limit and its repercussions, it was a relief to finally throw a leg over the new greenie and answer a few questions for myself.

Has the extra 36cc really made any noticeable difference to the ZX-6R, and has it improved the bike? My short answers are yes and yes.

WAY BACK WHEN
Back in 2000, the ZX-6R scored all-aluminium cylinders in place of the steel liners of earlier models. So for 2002 Kawasaki saw the resultant extra meat around the cylinders as a good excuse to increase bore size from 66mm to 68mm (hence 636cc). However, it wasn't a case of simply swapping barrels.

In order to create the required extra gasket area, new cases were necessary. Kawasaki also threw on a new cylinder-head with a revised squish area.

Before any of you older-model ZX-6R owners get excited though, it's not possible to simply replace the standard cylinders with the big-bore versions. Pity. It would have been a good way to surprise your mates!

Other than the displacement boost, the 636 has been subjected to few other changes. Pragmatic stuff - what has always been a good seller for Kawasaki Heavy Industries didn't need too much changing.

There are new mirror stays, which actually improve the view to the needle and clock speedo and tacho (now looking a little dated), a re-positioned front brake fluid reservoir, some tweaks to the front forks and various other small changes. There are new graphics as well.

DYNO POWER
There was plenty of opportunity to sample the improvements while the 636 testbike was in AMCN's possession, the tenure including a fang to the Snowy Mountains (NSW) and back, commuting and some good old fashioned scratching.

The bike was also run on the PTR dyno - and how it tells a story. The accompanying graphs show the 636 to have the edge on the 2001 model in power and torque from 3000rpm, before meeting up again around the 11,600rpm mark.

The new bike has a slight advantage in absolute peak power as well, but there isn't much in it. What the graph proves is that there is 3-5ps more through the mid-range - exactly what Kawasaki claims for the new model.

By the seat of the pants, the extra midrange ponies are noticeable, and a lazy rider can get away with short-shifting everywhere - both while scratching on weekends, and on the daily commute.

While this modus operandi will do the job, the green screamer still needs its neck wrung to get it up and boogying - it remains more a 600 than a 750 or larger.

EXTRA ZAP
But the practicalities are certainly there. On the superb, tight and twisty Jamieson-Eildon (Vic) road, I tried exiting corners with as little (for a 600) as 7000rpm on board. The throttle response was clean and crisp, while forward momentum was effortless, though hardly frenetic.

Exiting a gear lower rewarded me with improved scenery-blur, but ultimately wasn't that much faster and required more gear shuffling than the 'lazy' method.

Not that gear-shuffling was a chore. The box felt light and precise, and complemented the responsive nature of the engine very well. Whether the 1mm larger shift shaft has anything to do with that I'm not sure, but the gearbox is definitely a good thing.

I found myself zapping around in the midrange most of the time I was aboard the bike, just tapping into the upper reaches of the tacho when I needed a buzz - or wanted to impersonate Mr Pitt.

Speaking of buzz, the engine was as smooth as any other Kwaka, and the intoxicating wail from the airbox is much the same as the outgoing model. That wail intensified around the 11,000rpm mark, where the engine really felt like it was 'getting on the cam', punching the tacho needle hard towards the 14,000rpm redline. While maximum power is at 12,700rpm, it seemed like such a shame not to head for the red zone and use the over-rev facility, and luxuriate in one of my favourite sounds in motorcycling - a four-cylinder 600 nearing valve bounce!

And that's the beauty of this engine. You can torque the bike through town or around your fave back-road, but the fun, busy and rev-happy nature of a 600-class engine - the main appeal of such a unit - has not been lost. I like!

THE NEW ALL-ROUNDER
In fact the engine is just part of what makes the ZX-6R an excellent all-round package. Certainly the front fork mods seem to have improved an already good set-up, the front end felt as solid as a block of cement, and the damping rates maintained a degree of civility about them that was welcome on a long trip. The forks didn't knock the crap out of me, as some sportsbikes can.

Unfortunately the testbike was supplied with its front Dunlop D207 three parts knackered, and the rear not a lot better. With no time to secure a new set before the trip to the Snowys, I had to make do, and it is testament to the front end that it performed as well as it did. I can only imagine how it would feel with a fresh set of rubber!

Despite the condition of the front hoop, the 636 steered very well and kept issuing a steady, but not overwhelming, amount of feedback to yours truly. An excellent road set-up.

I only played fleetingly with the easily accessible suspension adjusters, mainly just to check they made a difference. They did, and will allow a fussy owner to fine-tune the forks to their liking.

The rear suspension too did the job, coping well with the luggage strapped to the back on the long ride, and working well over the many bumps of roads such as the Alpine Way. Adjustment was a piece of cake, and made a noticeable contribution to customising the ride.

As usual for a ZX-6R, the twin six-piston Tokico front brakes worked a treat. At first they seemed a little wooden in feel, despite having good power, but improved once the kilometres mounted. I put that down to the fact that this particular testbike had done quite a few laps at Eastern Creek during the recent national launch, and they had glazed over somewhat. I hardly noticed the rear, so it must have been working well enough.

TO BE FAIR
As it turned out, the 636 ZX-6R makes a surprisingly good sportstourer. At 178cm, I found the ride position pretty much spot on, remembering that this is still a sportsbike. The 'bars are low and the footpegs high compared to a genuine sportstourer, but were definitely on the roomy side for a 600-class bike - about on a par with Honda's CBR600F4i.

The fairing protection remains the best in the class and the bike is slim to sit on - nestling in between the Suzuki GSX-R600 and Yamaha R6 - and feels as if the 172kg claimed dry weight (1kg up from last year) is about spot on. On the move, it certainly felt light and manoeuvrable, as a 600 should, and was a delight on the non-stop corners of the Alpine Way.

Luggage attachment is also a cinch, as is taking a pillion (either/or) - the wide rear squab and large grab handles can accommodate baggage with ease. The petrol tank can also accommodate a tank bag.

A curious feature of the bike was the amount of steering damper bosses mounted to the frame. I counted three, all in different places around the head stem - maybe Kawasaki plans an assault on the Isle of Man TT. Don't they use three dampers at once over there?

One thing I didn't like was the fuel tap; the ZX-6R is the last bike in the class to still use one. Fumbling around for the reserve tap while the bike threatens to splutter to a stop is much more of a hassle than a fuel light blinking on - particularly when wearing winter gloves.

FUEL MISER
Mind you, switching onto reserve didn't happen too often - fuel economy was excellent. My Snowys trip averaged 18km/lt, with town running achieving 16km/lt. Combined with an 18lt tank, it makes for an impressive fuel range.

Another impressive thing is the finish. All the panels line up, and the paint quality is top notch. The new paint scheme is also one of the best to grace the ZX-6R range in my humble opinion, and it looks good on the road, as does the red version.

So, is the capacity increase worth it? Yes, the ZX-6R is a better roadbike as a result. The new engine lifts the already impressive ZX-6R to another level, complemented by the other mods, especially the front fork changes.

As far as the ZX-6R meeting its design brief, I believe Kawasaki has nailed it right on the head, and the new model stands in good stead to maintain competitiveness in a ferocious sales class.

At $14,590, the ZX-6R offers a lot of bike for the money. With competition like the $14,299 Yamaha YZF-R6, Suzuki's GSX-R600 ($14,390) and the Honda CBR600 F4i ($14,690) it has to, though the ZX-6R is the only of the group to have undergone major changes.

The 636 is a bike that will suit a wide variety of applications, and perform them with character and style. A truly good thing.