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.

Learn about suspension
As I said I am not going to reinvent the wheel when dealing with suspension so further down the page you will find a selection of links to guides to teach you about suspension. These are good guides and range from basic to more technical. I thoroughly recommend you read at least some of them (especially the Ohlins one) before tackling the task.

Now let's outline a few rules: 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.

Suspension Setup Guides:
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: 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 Height Adjusters?/Drop forks Adjusters/Drop forks Drop forks Adjusters/Drop forks Drop forks Adjusters/Drop forks Drop forks
Front Preload n/a? n/a Adjusters n/a Adjusters n/a Adjusters
Front Rebound 13 Way 13 Way 13 Way 13 Way 13 Way 13 Way 13 Way
Front Compression n/a n/a 8 Way n/a 8 Way 8 Way 17 Way
Max Front Wheel Travel 120mm 120mm 120mm 120mm 120mm 120mm 120mm
Rear Ride Height n/a Adjustable Adjustable Adjustable Adjustable Adjustable Adjustable
Rear Preload Adjustable Adjustable Adjustable Adjustable Adjustable Adjustable Adjustable
Rear Rebound 4 Way 4 Way 4 Way 4 Way 4 Way 4 Way 22 Way
Rear Compression n/a n/a 25 Way n/a 25 Way 20 Way 22 Way
Max Rear Wheel Travel 140mm 120mm 135mm 135mm 135mm 135mm 135mm


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 showing 8 rings showing n/a 8 rings showing n/a 6.5 rings showing n/a
Deck Height mm 0 3.11 3.11 5 10 0 10
Front Preload n/a? n/a 8 rings showing n/a 8 rings showing n/a 4 rings showing
Front Rebound 4 Clicks from Max 7 Clicks from Max 7 Clicks from Max 7 Clicks from Max 7 Clicks from Max 7 Clicks from Max 7 Clicks from Max
Front Compression n/a n/a 4 Clicks from Max n/a 4 Clicks from Max 6 Clicks from Maxs 12 Clicks from Max
Rear Ride Height (at shock mount) n/a 0 8mm 0 8mm 0 8mm??
Rear Preload 10mm less than free length 8 8 8 8 13 13
Rear Rebound position 2 position 2 position 2 position 2 position 2 position 2 8 clicks from max
Rear Compression n/a n/a 7 clicks from max n/a 7 clicks from max 15 clicks from max 7 clicks from max