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Setting up the suspension

Many people far more knowledgeable on this subject than I am have written loads on suspension setup. The information is not hard to find, but people still find it either hard to use or don’t believe it makes much of a difference. Believe me it does!!!
To top that the literature out there is very generic, but there are a few things specific to ZXRs/ZX7Rs and that is definetely worth knowing about before you start tweaking.
This page aims to provide you with exactly that information. You also will find here details about suspension adjustments available on specific models as well as the standard setups for each.
You may also want to take a look at my own setup data for my ’91 ZXR750R-K1 and my ’99 ZX7R-P4.

Now let’s outline a few rules:

  • Make sure your tyres are in good condition and correctly inflated and the wheels balanced (otherwise you may just be wasting your time).
  • Your chain must be lubed and correctly adjusted!!! A lose chain will snatch under acceleration and a tight one could lock up the suspension which defeats the object altogether.
  • ALWAYS make notes of the setup you are starting from, you may want to go back to it. Don’t assume your bike was prepped with the correct standard settings by your garage. Check it out for yourself!
  • ALWAYS make note of every change you make and, after a test ride, write down next to them your findings even if they are not positive.
  • Try to experiment to see what effects an adjustment can have.
  • Never make more than one change at the time…
  • …However if a change does not quite seem to work it does not necessarily mean that it was wrong. It may just be that you need to change something else as well for it all to work well.
  • Remember that the effect of each adjustment you make at the rear end will also be felt at the front and (to a lesser degree) vice versa.
  • Stiffer is not always better. Be realistic. If you spend 99% of the time on pot holed roads you really don’t want a bike set up to handle well at 190mph on a smooth racetrack as it will pulverize your spine and will force you to ride much slower than you otherwise could.
  • Somebody else’s “perfect” setup may be completely wrong for you and your riding style. By all means try things out, but always judge for yourself.
  • Don’t ride like a lunatic when you are testing your changes. Falling off at 120mph is a poor way to find out your changes didn’t work quite as you expected.

Basic principles:

Ride Height:Determines steering speed and weight distribution. This is normally the place where to start setting up a bike
Preload:This is the amount by which the spring is pre-compressed (by adjusters) to get it to work in its optimum range. You can vary this to get the suspension to work optimally for your weight. You should make sure the preload is right for your weight before you start making damping adjustments
Rebound:Controls how fast the suspension extends after having been compressed by a bump, braking and accelerating.
Compression:Also called “bump damping”. Controls how fast the suspension compresses when hitting a bump, braking (controls front end dive) and accelerating (controls rear end squat).

Terminology:

Deck Height:This refers to how far the forks protrude above the top yoke (can be 0)
Stanchion:The chromed part of the fork that slides into the fork slider.
Yokes:Also called triple clamps. They are the bits that clamp the forks and pivot on the steering stem.
Rake:Also called Steering head angle. Between 23 and 25 degrees is normal for today’s sportsbikes. The smaller the figure the quicker the bike will turn. However too small figures will cause the bike to be too unstable for the road and beyond a certain point it would start affecting the suspension action by causing too much flex in the forks stanchions. The rake is affected by lowering the front ride height (or raising the rear) as this effectively gives a smaller rake hence quicker steering.
Suspension travel:Also called wheel travel. The maximum amount of vertical travel of each wheel ranging from suspension fully extended to fully compressed
Wheelbase:Distance between the front and rear wheel axle. It can be varied by using a shorter chain or a bigger rear sprocket (the sprocket change also affects acceleration at the expens of top speed), but scope is limited. A longer wheelbase gives more stability, a shorter one makes it easier to turn the bike
Static Sag Without rider:This is the amount the suspension sags (from fully extended) under the weight of the bike alone held upright.
Static Sag With rider:This is the amount the suspension sags (from fully extended) under the weight of the bike and the rider fully kitted out (feet on the pegs). You will need a mate to keep you and the bike upright whilst another takes the measurements.
Clicks from Max:Screw adjusters are normally at Max when turned all the way in (clockwise). These adjusters are stepped and make a small audible click when turned by set amounts hence clicks from max is number of clicks from the “fully in” position.
Bottoming out:Refers to when the forks dive so far (e.g. under braking) that they hit the stop (no more travel left).
Topping out:Reverse of above. Here the suspension extends until max range has been reached. Any further and the wheel looses contact with the ground

When starting to set up your suspension for the first time do it in this order:
Step 1: Check the ride height and adjust if necessary (See my step by step guide to Dropping the forks and adjusting rear Ride Height).
Step 2: Check the Preload at both ends (if your model has adjusters for it) and adjust if necessary.
Step 3: Check the damping and adjust if necessary.

 


Data specific to ZXR750s/ZX7Rs


 

Important Points:

Point 1:
J, L and P models (not sure about H models) have no preload adjusters. The adjusters on top of the forks are ride height only.
Try this test if you prefer to verify this for yourself.
K, M and N models have front preload adjusters.

Point 2:
H, J and K models have a notoriously hard rear shock (K model a little less so) which only seems to work OK for heavier people. This is apparently due to a spring that is too stiff, too much damping in the shock and the rising rate of the shock linkage not being linear enough. If you are suffering from this here’s what you can do:

(H, J, K models)Buy a softer shock spring tailored to your weight. Not a complete cure but better than stock and a fairly cheap solution
(H, J, K models)Buy an aftermarket shock. A more expensive option, but a better one in my view.
(J, K models)Use a shock linkage from an L, P or N model, all of which have a more linear rates (not that of an M model though as it has the same rate as that on J and K models). This is a great and very cost effective solution. See K1 suspension Mods and also suspension setup 2 on ’91 ZXR750R-K1 for more info on my K1 running a “P” model linkage.
(H, J, K models)Get a new shock linkage from NWS (they make one specifically designed to cure this problem).
(H, J, K models)Use both an aftermarket shock and one of the above shock linkages (likely to be the best solution). Beware though! When you buy the new shock it is best to tell the supplier about the new linkage as the shock may need to be tweaked to compensate (See note at K1 suspension Mods)

Point 3 – Ride Height:
A lot of people have asked me how to drop the forks or change the rear ride height on ZXRs and ZX7Rs, so here’s my step by step guide to Dropping the forks and adjusting rear Ride Height

Adjustments you have available when setting up your model of ZXR or ZX7R:

  • Front ride height: On J, L and P models (not sure about H models) it can be varied by using the adjusters and/or dropping the forks. On K, M and N models it can only be adjusted by dropping the forks
  • Front preload: J, L and P models (not sure about H models) have no simple way of changing front preload. You can either buy new springs or you could make different spacers that sit differently inside the forks from the standard ones. These convert the adjusters to preload.
  • Front Rebound: All models are adjustable
  • Front Compression: H, J and L models have no compression adjustment, K, M, P and N do.
  • Rear ride height: All models (apart from the 89/90 H models) have a rear ride height adjuster separate from the preload adjuster.
  • Rear Preload: All models are adjustable
  • Rear Rebound: All models are adjustable
  • Rear Compression: H, J and L models have no compression adjustment, K, M, P and N do.

Here’s a table to summarise and give adjustment ranges. For more detailed info see the specification pages under History & Specs. I put question marks(“?”) where I either had no data or was unsure of the data itself.

 

Adjustments available & Suspension data
 

Models in Chronological order
H
J
K
L
M
P
N
Front Ride HeightAdjusters?/Drop forksAdjusters/Drop forksDrop forksAdjusters/Drop forksDrop forksAdjusters/Drop forksDrop forks
Front Preloadn/a?n/aAdjustersn/aAdjustersn/aAdjusters
Front Rebound13 Way13 Way13 Way13 Way13 Way13 Way13 Way
Front Compressionn/an/a8 Wayn/a8 Way8 Way17 Way
Max Front Wheel Travel120mm120mm120mm120mm120mm120mm120mm
Rear Ride Heightn/aAdjustableAdjustableAdjustableAdjustableAdjustableAdjustable
Rear PreloadAdjustableAdjustableAdjustableAdjustableAdjustableAdjustableAdjustable
Rear Rebound4 Way4 Way4 Way4 Way4 Way4 Way22 Way
Rear Compressionn/an/a25 Wayn/a25 Way20 Way22 Way
Max Rear Wheel Travel140mm120mm135mm135mm135mm135mm135mm

 

Standard Setups

Please note that for standard rear preload settings the figures are as quoted by Kawasaki i.e. 20mm does not mean 20mm of visible thread, but rather that when the spring preload has been set the spring (without load on the suspension) should mesure 20mm less than it “free” length.

Models in Chronological order
H
J
K
L
M
P
N
Front Ride Height (rings showing)6.5 rings showing8 rings showingn/a8 rings showingn/a6.5 rings showingn/a
Deck Height mm03.113.11510010
Front Preloadn/a?n/a8 rings showingn/a8 rings showingn/a4 rings showing
Front Rebound4 Clicks from Max7 Clicks from Max7 Clicks from Max7 Clicks from Max7 Clicks from Max7 Clicks from Max7 Clicks from Max
Front Compressionn/an/a4 Clicks from Maxn/a4 Clicks from Max6 Clicks from Maxs12 Clicks from Max
Rear Ride Height (at shock mount)n/a08mm08mm08mm??
Rear Preload10mm less than free length88881313
Rear Reboundposition 2position 2position 2position 2position 2position 28 clicks from max
Rear Compressionn/an/a7 clicks from maxn/a7 clicks from max15 clicks from max7 clicks from max

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