zx9r hard suspension

[almostthere]

Any ideas how I can soften the suspension on my zx9r B2 I'm sick of banging and crashing over bumps and potholes.
It must have been setup for a right fat bastard
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Beer, It's the reason I get up every afternoon
www.mfairco.uk

[Old Git Racing]

Start by setting the suspension sag when you are on it. Measure from a fixed point on the bike without you, then get on it and back the spring preload off front and rear until it goes down 25mm front, 35mm rear. Might need someone to give you a hand. Then go on google and find a base setting for the compression/rebound damping settings and adjust as required.
The Kwacks I've had always had way too much spring preload dialled in as standard.

OGR.
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2022 Tiger Sport 660 2019 Street Twin 2003 K3 gixxer 1000 1998 Srad 600 track hack

[bacon]

Lots for components in suspension to consider:

The easy ones to setup yourself are you preload, compression and rebound

Preload:
You want 25 to 30% of total travel in rider sag (that's sag with you fully kitted sat on the bike). Get a friend to help, loads of tutorials on YouTube on how to do it if you are unsure.

Preload only adjusts ride height, not stiffness and as such affects where in your suspension travel the bike operates.

If you max out your preload to get the right rider sag, your springs are too soft, if you have backed all preload off and you still don't have enough rider sag your springs are too stiff.

Rebound:
Back out the adjust from fully closed and count the clicks, that is how much adjustment you have available to you.
Push down on the forks (or seat for the rear) and release any pressure you have on it to let it extend back to its resting position.

You want it to bounce only once and then immediately settle down. If it bounces too much, add some rebound and try again. Keep going until it is set roughly in the right place. You can adjust once you have ridden it.

Compression:
Back out the adjuster from fully closed and count clicks again, set it roughly half way and go ride it. Try and do the same corners over and over again, and adjust from there. I'd go softer each time as you currently find it too stiff.

The owners manual should have suggested settings if you are unsure of playing with the rebound/compression yourself. Soften it up from the stock settings a bit at a time.


If it's still too harsh you can change your springs, replace fork oil at the same time, it's easy and should be done far more regularly than most people do it, check the manual/internet for oil viscosity. Find the rating in "cst", don't go by oil weight in W, I.e 5W, 10W. The same 5W of different brands can vary massively in oil viscosity, measured in cst.

From my recent research, cartridge forks tend to use oil with a viscosity between 15 to 20ish cst at 40C.

If it's still too harsh then you may need your suspension opened up and revalved/re-shimmed.

Edit: oh and not forgetting the oil level (air gap), this acts like another spring, at the upper end of fork travel.

Tldr: keep it simple to start, adjust back to base settings (incase they have previously been adjusted to very stiff settings) and adjust your preload. Then go from there