MARCH 2001

Pages 112-113 PB


You can't get better than a quick, fit Kwacker. And for a reet fit ZX-6R it only takes a few tweaks of the suspension and a play with the tyre pressures, says Trev…



Every couple of years, Kawasaki unleash an upgraded version of their 600cc ZX-6R. And it's always a bike superior to the last one. But, strangely, still not deemed good enough, or rather fancy enough, to capture that elusive best-seller title. Not for the want of trying: ZX-6R motors have all been power-houses; chassis likened to a brick outhouse; and brakes always up to the job. The year 2000 model (J1) is no exception.


The J1 has another attribute, which is also overlooked: suspension that works better than the competition's. OK, so it isn't race perfect but then not many bikes are. But for stock, built-to-a-price stuff, it'll do for track day junkies. Saying that, like anything that's adjustable, it is a11 too easy to get it wrong.


Circuit Pau Arnos in southern France is a mixture of slow, fast, uphill and down dale turns. Coupled with lunch-filled riders, suspension and brakes are used to the full. On the ZX-6 there was plenty of seesawing effect as the front end dived under braking and sprang back with the brakes off.


It was the same story at the rear, squatting with a fist full, and a slight lurch/wallow sensation over harsh bumps. At the same time, the front end felt vague mid-turn and on a steady throttle. At standstill the reason was obvious. Pushing down hard on the top yoke would see the forks dip, then spring back easily. The front end was literally floating on its fork springs. Understeer reared its head, too. Powering out of turns, the bike would end up closer to the outside edge of the track than was healthy. This was a sign the bike's ride stance needed more of an arse up, nose down attitude, and maybe there's not enough rear compression damping.


Raising the easily accessible rear ride height adjuster by 8mm sharpened the steering by 100%. Where wrestling with the clip-ons and getting off the seat was necessary to get it on its side, shifting bodyweight would now pitch it over. This simple adjustment also put more weight over the front end to give slightly more feel for what the front wheel was doing. Understeer wasn't mentioned again.


Although the 8mm of ride height didn't make the bike unstable, certainly not with Metzeler MEZ3 Racing tyres, a quick-steering bike is not everyone's cup of tea. To reduce understeer and only slightly sharpen the steering, just 4mm of ride height does make a difference.


More feedback came by adding more front preload to take out unwanted sag. Our final setting was four lines showing, the fourth line level with the top of the fork-top nut.

It was next a case of slowing fork dive (compression) and the return to full length (rebound/extension).



Preload                Kawasaki quote 14mm


Rebound              7 clicks out from full in

Compression        9 clicks out from full in



Preload                spring length set at 180mm

Rebound              ten clicks out from full in

Compression        ten clicks out from full in

Ride height          zero



Preload                4 lines showing

Rebound              4 clicks out from full in

Compression        6 clicks out from full in



Preload                one full turn back if weighing

                           less than 14 stone

Rebound              7 clicks out from full in

Compression        8 clicks out from full in

Ride height          +8mm



A 6R with knee sliders. Leather ones at that.


Rebound ended up as four clicks out from fully in. Screw clockwise all the way in till the adjuster can't turn, then go back until a click is felt. This is position one. Then turn the adjuster for another three clicks.

Final setting for compression was all the way in clockwise, then back out six clicks. The front end was transformed. Smooth and progressive on or off the brakes, a tauter, tell­ all ride, but still compliant on the rough and bumpy stuff.


At the back end, it was a similar tale. Rebound set at seven clicks out from full in, compression eight out from full in. There was a slight argument in my head on the subject of rear spring preload. Like where it should be set...


I thought the bike felt better on the stock setting (180mm spring length). Gus, on the other hand, being three stone lighter (a conservative figure that), seemed to favour less preload. One full revolution back of the locking rings to give (approx) 186mm spring length. It seems the ZX-6R has a pretty hard spring as standard. And anyone over 14 stone (without leathers, helmet boots etc on) would be advised to stick with the standard preload setting.


Happy R6 hunting...




Compression adjustment is best done by creeping up on the bike, downwind and with rubber-soled shoes - that way it can't escape



 When we say all the way in, we mean clockwise till it stops. Then back off to the desired position. Rebound, in this case, four clicks


A heftier tool is required to adjust preload. A quality spanner should be used - worn jaws will bugger anodising and mangle the alloy


In the harsh glare of a flashlight, the ZX-6R's rear rebound adjuster is found. WD40 applied regularly will prevent seizure from road crud


Maxton can revalve and respring the standard unit. That is if you're unhappy with a hard spring best suited to 14 stone-plus biffers



Unlike step-type preload adjustment on most 6 bikes, this `thread-type' is more precise. And a good way to blunt screwdrivers undoing lock rings



Ride height in its standard position. To raise: undo the upper nut (22mm) until it nears the split pin. Now find a 8mm drill bit and insert...



……between the underside of the nut and shock mount. Wind the nut down so it's a sliding resistance to get the drill out - like a feeler gauge


Now lift the rear of the bike to take the weight off the bottom lock nut and wind it up to the underside of the mount before locking off


Metzeler MEZ3 Racing tyres suit the ZX-6R very nicely, thank you, Mr CPK. Final pressures at a cold track were: 31 front, 32 rear


Just for a change, Kawasaki's ZX-6R rear shock is one that we can revalve. And it needs it. The shock is underdamped, mainly rebound rather than compression, and the rear spring is what we would call hard. Because of the shortfall in damping, and despite the firm spring, the bike tends to ride on the spring. The rear will squat under power and run wide coming out of turns.


We can change the rear spring for a softer item. The type depends on the weight of the individual and whether for track or road, or both. Our revalve work (re-shim and modify damper

cartridge) will give a damping curve similar to our own Maxton shock. But we can't widen the range of adjustment. You're looking at £123.40 for this conversion. Our Maxton range of fully adjustable shocks starts at £475.90.


The forks carry too much compression damping - kicking hard off bumps with not enough rebound. The springs are on the softish side, but not as bad as, say, a CBR600. To revalve and reshim which will reduce compression and give a greater range of adjustment, plus suitable springs, will cost £229.




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