rebound and compression settings

[T0MMY]

Anyone got any tips for a baseline for the suspension on my ZX6R G2 (75-80kg rider)? I have a trackday tomorrow so I will play with the settings a bit between sessions but it would be useful to have a starting point as it handles pretty poorly at the moment. The preload is set ok so I'm more interested in the damping.

I've hardly ridden the bike yet but gave it a bit of a run after work and found it spins up the rear wheel a little too easily out of corners. I was coming off a roundabout leant over reasonably far at about 70mph and found the back wheel skipped and bounced and slid out quite far under hard acceleration. I suspect this might be due to too much compression damping but I don't really have much experience with setting up suspension.

It also feels like the front flops into corners too much and feels like it's trying to tuck under but it does have a leaky fork seal so that may be the culprit! It also has a 120/70 on the front which is steeper than standard so will add to that I guess.
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ZX6R + CBR600RR

[Howling TerrorOutOfOffice]

My 2p.
Pay the bloke a tenner to set it up.

You have lost some fork oil. How old is the oil? Are the springs past their best?
You might only be doing a trackday, but it comes across that you want to actually improve.
Learn from the professionals or set to stock and start adding clicks.
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Diabolical homemade music Bandcamp and Soundcloud
Singer songwriter, Artist and allround good bloke Listen to Andrew Susan Johnston here
The Harry Turner Project

[T0MMY]

If I can get a setup at the track for a tenner I'll go for that. I thought it would be a lot more and not worth it if I'm looking at fixing the fork seal, changing the fork oil and maybe getting a new shock on there plus I will be getting some decent race scrubs on it too.

I would like to improve but really I just want it to handle at least as well as my venerable CB-1 I'm still tempted to just take that bike instead frankly as it's awesome for what it is and it would be fun trying to keep up with the superbikes
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ZX6R + CBR600RR

[Howling TerrorOutOfOffice]

The tech people might not want to work on a bike with a leaky seal?

Whatever you choose to do including if you do take the CB-1, have a butchers at this.

https://www.moto-racing.co.uk/Guides/motorcycleSuspensionSetup.htm
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Diabolical homemade music Bandcamp and Soundcloud
Singer songwriter, Artist and allround good bloke Listen to Andrew Susan Johnston here
The Harry Turner Project

[T0MMY]

Thanks for the link, should be useful.

The CB-1 is really well set up, handles beautifully for what it is and has utterly superb tyres. It's limited by the ground clearance more than anything else and by the lack of power so I don't think I could go a lot faster on it. I bought the ZX6 to improve my riding by trying to reach its (much higher) limits but with the current set up I suspect that tomorrow I will be limited by the rear suspension more than my own ability (or lack thereof).
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ZX6R + CBR600RR

[neatbik]

You will need to get that fork seal sorted out really before anything else.
Other than that, try setting everything in the middle and take it for a ride.
Post back with your findings and we can take it from there.


When i had my CB1 i very nearly fitted a pair of cbr400 forks (go straight in and are adjustable) and a 'blade rear shock.
Would have transformed it i reckon.

[T0MMY]

As I said, biggest problem with the CB-1 is ground clearance and rearsets are hard to find for it. Also hard to get race scrubs for it, plus it's still a pretty slow bike. All in all I decided it was better to get something more track orientated as it'll be easier to get suitable parts for it. I never felt the CB-1 was let down by the suspension really as it had more grip on track tyres than the power could overwhelm anyway.
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ZX6R + CBR600RR

[SirEdward]

[Old Git Racing]

[MarJay]

That link is too complicated.

You want this:

https://www.bikechatforums.com/files/setup.zip

It is a PDF but too large to attach to a post in BCF. However, its only three pages long and explains pretty much all you need to know.
____________________
British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F; Cheap project: CBR900RR FireBlade
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[MarJay]

[Old Git Racing]

Tommy, sorry about that, reading it now it does come across as nasty, you're right Marjay. I can be a dick sometimes like anyone and I was posting that crap.

On a more helpful note Kwaks usually are oversprung so you need to get the sag set up first and go from there. At a track they usually charge 30-40 quid to set it up but just find someone who looks fast on a similar bike and ask them their opinion first. Get tyre pressures right for the track, stick a tie wrap round a fork leg (the one not leaking ) and set the front so you have about 10mm of movement left after your hardest braking. set the rebound so the forks come back up progessively, not just springing back up when you come off the brakes, bet you end up not far from maximum on rebound.
At the back its more about feel. Set compression so the bike doesn't sit down too much when you get hard on the gas, but not hard so that itcompromises grip on bumps. Set rebound so the back comes up at the same speed as the front, again bet its close to max.
Hope this is a bit more helpful and have a great day.

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

[T0MMY]

Didn't get a chance to read that before I went...

ZX6 was ok, first session out it was way too soft at the front under braking and the back was bouncing around a lot leading to 2 BIG slides. I cranked up the rebound and compression at both ends and it was much much better but I was really held back by the lack of grip of the rear tyre which was spinning up out of just about any corner and really limiting lean angles too. It ruined the day to a certain extent as I was having to ride below what I would consider my limits but I guess I learnt a bit about being smooth.

For the record, a CB-1 with well set up suspension and Michelin Power Ones does handle better than a ZX6R with a rear BT020 and poor damping. I've no doubt I was quicker on it in the corners as it just has so much more grip.

All in all just glad I made it home as I had at least one "moment" on every lap to the point where sliding the bike out of certain corners was starting to be the norm.
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ZX6R + CBR600RR

[SirEdward]

Reduce rebound by 50% & compression by 25% of what you have on the rear shock, otherwise the rear wheel will spin out of corners, because you're not fat enough. I've cranked up compression on my old 750 SRAD due to 11 y.o. suspension, and it is more stable now during braking & acceleration - a new bike.
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"Beyond a critical point within a finite space, freedom diminishes as numbers increase. This is as true of humans as it is of gas molecules in a sealed flask. The human question is not how many can possibly survive within the system, but what kind of existence is possible for those who so survive.

Pardot Kynes in "Appendix I: The Ecology of Dune""

[jay12329]

[Old Git Racing]

Have you measured the sag? Still sounds like too much rear preload to me, if it is it will overcome the damping and not let it work properly.
Reducing compression and rebound will perpetuate the problem if the spring is too hard, particularly rebound cos as the suspension extends too quickly you loose grip.

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

[T0MMY]

One of the instructors went over the suspension settings for me and we tried various things.

Lower damping (both ways) on the rear led to the back wheel skipping out of corners, the best setup was everything pretty much as stiff as possible. With this setup the bike felt good at the front and stable all round but I was still unable to get the power down as easily as I would have liked and lean angles similar to what I could easily achieve on the CB-1 led to the back wheel drifting wide (but in a much more controlled way than in the early sessions). Applying power, therefore, was somewhat nerve racking

The guy agreed with me that the tyre just didn't have the grip to push harder. To be honest though, we should put this in perspective...I had no trouble keeping up with most of the guys in inters and overtook a lot more than I got overtook, I think I was just spoiled by the excellent tyres on my CB-1 and am disappointed with the grip of this bike. The bike was far from hopeless, I just wish I was being held back by my own lack of skill or even the true capabilities of the bike rather than just a lack of grip from one tyre.

EDIT: Forgot to say...the other possibility is that I was going off the edge of the tyre as it doesn't have a very steep profile. The little curls of rubber you get were being pushed right off the edge of the tyre so I guess it's possible though a little surprising considering I never felt like I was leaning all that far.
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ZX6R + CBR600RR

[skyline]

Bt020's and 021's are shockingly poor on track. At Mallory I went out on bt021's for the morning sessions as I didn't want to put my slicks on due to not knowing which way the weather was going (cold morning and lack of tyre warmers put me off to!) and I lapped 6 seconds slower on average though 3 sessions than I did running wets in the wet a few months earlier. Slicks back on after that and my times dropped straight down even though I didn't feel like I was leaning more or pushing all that much harder but I sure as hell passed more people lol! Bt021's I was riding would spin up far to easily without having to push to much out of corners. For me Id say tyres have the biggest impact on how I ride, although I think Ill be looking at getting suspension set-up done next perhaps

[Deckx]