Stock GSX-R 600 k8 suspension help

[dipshit]

Have been having a bit more of a tweak on my 600's suspension today. It is all stock apart from re-springing the rear shock from a 9.4kg down to a 8.5kg spring to suit my 78kg weight better. The change in spring certainly improved things and i no longer get my backside launched out of the seat on any decent bumps.

I have backed off compression damping a bit at both ends too (more so the rear) to see if any improvement again can be had. The bike now feels more stuck to the road than the harsh skipping/floating along the top of the road surface feeling it had before.

But there is still a harsh feeling from the rear shock that doesn't seem quite right yet. I have been backing off rebound on the rear quite a bit, but it doesn't seem to be making much of a difference yet. There is still a feeling the rear end is pumping down over a quick series of bumps.

My question is should i keep reducing rear rebound... or is this some limitation in the standard shock and i should look at getting a re-valve... or am i on the wrong track altogether with my settings..???

Any advice would be appreciated.

[Pussy]

I can't really give you any advice on the stock shock, dipshit.
I would advise, however.... a TTX36. They are very compliant and controlled.
I think RT has revalved a stock K6-K9 600/750 shock, but I don't know how it performed.
I have only done about 400km on a stock shock in my 750, and I didn't like it that much


Edit: The bike felt "wooden" with the as delivered shock on it

[Morcs]

I hate the fact im helping you but...

Drop the forks so about 5mm sits above the top clamp.
Front preload - about 8 turns out from fully in (from stiff end of scale)
Front rebound - 1 turn out from fully in (from stiff end of scale)
Front compression - 2 turns out from fully in (from stiff end of scale)

Rear, given the change of springs, have about 6mm of thread showing.
Rear rebound - about 2 and a half turns out from fully in (from stiff end of scale)
Rear low speed compression - 1 and a half turns out from fully in (from stiff end of scale)
Rear high speed compression - 3 turns out from fully in (from stiff end of scale)

Dial those settings in and see how it goes. Its a definate good starting point for fine tweaking

[dipshit]

I can't really give you any advice on the stock shock, dipshit.
I would advise, however.... a TTX36. They are very compliant and controlled.

That would be an option before i threw too much money at the standard shock.




Edit: The bike felt "wooden" with the as delivered shock on it

That's a very good description of the feeling i'm experiencing too. It's not responding very well to damping changes.

[dipshit]

Dial those settings in and see how it goes. Its a definate good starting point for fine tweaking

Thanks. At least i can compeer these against standard settings and what i have done to see if i have ended up going down the wrong path.

However it looks like my settings are quite close or heading in the same direction as those.

[dipshit]

I hate the fact im helping you but...

Drop the forks so about 5mm sits above the top clamp.
Front preload - about 8 turns out from fully in (from stiff end of scale)
Front rebound - 1 turn out from fully in (from stiff end of scale)
Front compression - 2 turns out from fully in (from stiff end of scale)

Rear, given the change of springs, have about 6mm of thread showing.
Rear rebound - about 2 and a half turns out from fully in (from stiff end of scale)
Rear low speed compression - 1 and a half turns out from fully in (from stiff end of scale)
Rear high speed compression - 3 turns out from fully in (from stiff end of scale)

Dial those settings in and see how it goes. Its a definate good starting point for fine tweaking

Actually it looks like these are just Sport Rider's suggested settings (http://www.sportrider.com/suspension_settings/146_suggested_suspension_settings/suzuki.html) ... but thanks anyhow.

[Morcs]

Actually it looks like these are just Sport Rider's suggested settings (http://www.sportrider.com/suspension_settings/146_suggested_suspension_settings/suzuki.html) ... but thanks anyhow.

Heheh smart guy :)

They have a tendancy to work...

[crazyhorse]

Morepower helped me set my suspension up. We took it back to factory standard, and I've wound in the front abit (don't think we ended up touching the rear on it)

But yeah I still occassionally have my arse leave the seat over some bumps (but you get that at over 200 km/h), but nothing like it used to. PM him for advice, he's fairly good at that sort of guff.

[Toot Toot]

Just PM Shaun (thats his name on here) of Motodymamix. I have a K8 750, and he sorted it sweet as.

[Pussy]

It's not responding very well to damping changes.

I think a lot of the "adjustment" you can do to the stock shock is more a cosmetic thing. The adjusters look good!

The stock shock has a rubber bladder type thingie for separating the gas and the oil in the reservoir.... and the gas ends up emulsifying itself in to the oil. This can make adjustments null and void too

[dipshit]

The stock shock has a rubber bladder type thingie for separating the gas and the oil in the reservoir.... and the gas ends up emulsifying itself in to the oil. This can make adjustments null and void too

This wouldn't be the case on a shock with olny 2000 kms on it, would it?

[Pussy]

This wouldn't be the case on a shock with olny 2000 kms on it, would it?
Yep, it can be!
RT would be worth a call, dipshit.
Not just to buy a new TTX, either

[Shaun]

This wouldn't be the case on a shock with olny 2000 kms on it, would it?



When is your next track day< I may be able to lend you a set of modofoed forks as well as a modified Shock? Might be able to! PM me details please

[Pussy]

With any luck, dipshit, RT may pipe up and give you the gen on the internals of the stock shock

[Robert Taylor]

The shock is likely riding too low in its stroke so its getting to the rising rate part of the rear linkage curve too readily. Also the stock piston inside that shock maxes out in port area flow rate at relatively low velocities so revalving is not going to 100% successfully fix that issue. A Race Tech piston will make a huge difference as the port area flow rate closely mimics the more liberal flow characteristics of an Ohlins piston. It will also end up that the external clickers will end up with a half decent response range.
The front end seriously lacks high speed rebound damping control and we have modified in excess of 20 sets of these now. Id take up Shauns offer to try a set.
Be wary of suggested external settings from especially US mags, they ride on predominantly smooth roads and dont so much get the same frequency of suspension control issues that we do here on our rugged poorly maintained roads

[dipshit]

The shock is likely riding too low in its stroke so its getting to the rising rate part of the rear linkage curve too readily.

I have a lot of preload on the new spring. Less than 5mm free sag and around 25 to 30 mm rider sag. Have a preload spacer for the race tech spring as it was 16mm shorter than the stock one. I don't like the feeling of a bike sitting low in the rear. But of course the travel still could be reaching the rising rate.



A Race Tech piston will make a huge difference as the port area flow rate closely mimics the more liberal flow characteristics of an Ohlins piston. It will also end up that the external clickers will end up with a half decent response range.

This is good to know. It may be a viable option for me.



The front end seriously lacks high speed rebound damping control and we have modified in excess of 20 sets of these now. Id take up Shauns offer to try a set.

I have already planned and budgeted for getting the forks modified soon. It's just that I wasn't so sure about the rear shock and what to do about it.




Be wary of suggested external settings from especially US mags, they ride on predominantly smooth roads and dont so much get the same frequency of suspension control issues that we do here on our rugged poorly maintained roads

I know. Their recommended settings were quite far off from where I ended up on my last bike. I certainly don't place much weight on suggested settings from magazines and such.

[Robert Taylor]

There is another clue here, the compression shim stack opening pressure is actually TOO LIGHT, that is causing the shock to blow through its stroke too readily and ''get to the link''. By making the stack STIFFER ( With a few tricks that make the initial opening pressure stiffer but not at higher velocities ) it will ride higher in the more compliant part of link ratio

[dipshit]

So either modify the bejesus out of the standard shock or go the TTX route.

I will probably price both options closer to the time of doing something about it and weigh up the price difference.

In the meantime i will try increasing the low speed compression back closer to where it was and reduce the high speed.

[Pussy]

In the meantime i will try increasing the low speed compression back closer to where it was and reduce the high speed.

Probably the best bet, dipshit.
We got two brand new K6 750s a week apart in November 06, and even on completely stock settings, both bikes felt different at the rear.
I think there is a huge manufacturing tolerance with the OEM stuff

[dipshit]

Probably the best bet, dipshit.


I hadn't played with the high speed damping much because in the onthethrottle (http://www.onthethrottle.com/content/view/73/40/) tutorial, Dave Moss seems to suggest to set it (at one turn out or in or something) and leave it there... like it wasn't worth fiddling with.

[SVboy]

On my k9 750, I have set the static sags for my 75kg weight-long way out too!
Now I have checked the factory settings on all the clickers and have gone about a 1/4 turn towards soft on them all. I find the bike a bit stiff, very stable and a bit understeery on factory settings. I can see that dropping the forks 5mm thru the clamps would aid turn-in, but I hope softening up the front a bit will sharpen up turn-in[if I am on the brakes] Bike seems a bit harsh over square edged bumps-so softening of the rear for that reason. Any feedback appreciated.[Cant afford upgraded forks or shock at this stage-but in the plans!]

[Robert Taylor]

On my k9 750, I have set the static sags for my 75kg weight-long way out too!
Now I have checked the factory settings on all the clickers and have gone about a 1/4 turn towards soft on them all. I find the bike a bit stiff, very stable and a bit understeery on factory settings. I can see that dropping the forks 5mm thru the clamps would aid turn-in, but I hope softening up the front a bit will sharpen up turn-in[if I am on the brakes] Bike seems a bit harsh over square edged bumps-so softening of the rear for that reason. Any feedback appreciated.[Cant afford upgraded forks or shock at this stage-but in the plans!]

Moving the forks in the clamps by 5mm is going to assist, if its still needs a bit more reduce preload on the front springs by one ring.

[Pussy]

On my k9 750, I have set the static sags for my 75kg weight-long way out too!
Now I have checked the factory settings on all the clickers and have gone about a 1/4 turn towards soft on them all. I find the bike a bit stiff, very stable and a bit understeery on factory settings. I can see that dropping the forks 5mm thru the clamps would aid turn-in, but I hope softening up the front a bit will sharpen up turn-in[if I am on the brakes] Bike seems a bit harsh over square edged bumps-so softening of the rear for that reason. Any feedback appreciated.[Cant afford upgraded forks or shock at this stage-but in the plans!]

Your bike is sprung quite heavy out of the crate for your weight.
It's got 1.00kg/mm springs in the forks, and a 9.5nm spring at the back.
We've resprung one of our 750s to .90kg/mm front, 8.5nm rear, and it works well for the lighter of the two riders here

[98tls]

Fwiw dip when your next in Ommers why not call in to the local Honda outfit,as you probably know theres a couple of well clever with suspenders buggers in there,Shaun Harris recomended them to me yonks ago.

[Robert Taylor]

Your bike is sprung quite heavy out of the crate for your weight.
It's got 1.00kg/mm springs in the forks, and a 9.5nm spring at the back.
We've resprung one of our 750s to .90kg/mm front, 8.5nm rear, and it works well for the lighter of the two riders here

That is essentially correct but of course the rider has to decide on expenditure level. To sort it out properly it inevitably will need softer springing, no amount of external clicker twiddling will correct it. Most external clickers will only adjust damping by approximately 5%, this is more than a 5% problem.

[SVboy]

It is clear that the long term solution is the front/rear rebuild by Robert & co, certainly something I want to do as finances allow.

[dipshit]

Fwiw dip when your next in Ommers why not call in to the local Honda outfit,as you probably know theres a couple of well clever with suspenders buggers in there.


Yeah, i got the shock spring changed there. They did a good job with no problems.

I did try to talk about other modifications they could do... but didn't get any suggestions. I mentioned i may even consider an Ohlins shock possibly... but the idea was practically pooh-poohed as being overkill for me.

(Don't you just love it when race guys have all the good gear yet think us road users don't deserve any of it)

At least i know what services the guys up in New Plymouth are offering. Either a good excuse to travel up to the NI one day, or easy enough to pull the forks and shock out of my bike and courier them up.

[Robert Taylor]

I hadn't played with the high speed damping much because in the onthethrottle (http://www.onthethrottle.com/content/view/73/40/) tutorial, Dave Moss seems to suggest to set it (at one turn out or in or something) and leave it there... like it wasn't worth fiddling with.

Well I just rode a GSXR600 today and took high speed adjustment out of the rear ( loosened the adjuster anticlockwise ) and the high speed bump compliance was noticably improved, repeating a riding test over the very same bumps.
Dave Moss would likely have been referring primarily to road race where ride height control and lap times takes precedence over comfort.

[dipshit]

Well I just rode a GSXR600 today and took high speed adjustment out of the rear ( loosened the adjuster anticlockwise ) and the high speed bump compliance was noticably improved, repeating a riding test over the very same bumps.

Sweet... I will give this a try. :niceone:

[Robert Taylor]

Sweet... I will give this a try. :niceone:

In the first instance try backing it out anticlockwise by 1/2 to 3/4 turns

[SVboy]

I felt softening ALL the settings 1/4 turn made a noticeable improvement, both on track and on the road. Not that I am a 10/10ths rider! I have gone another 1/4 softer all round and will check out the impact of that.

[kudos@xtra.co.nz]

Just got back from CKT where Robert fixed up the suspension on a K7 GSXR 600. Using race tech components the difference is astounding. Dont bother meddling with settings, take a trip to New Plymouth and experience what real suspension feels like. He also did my Kawa 636 with the same results. The guy is a genius.

[SlideMoto]

(Don't you just love it when race guys have all the good gear yet think us road users don't deserve any of it)

Interesting you should say this because I was talking with a road rider a couple of days back looking for advice after taking the recommendations of others (racers) and spending a good load of coin on suspension "upgrades". He now lacks confidence in his bike and just wants it to be the way it was when he purchased it stock. horses for courses

[Pussy]

Interesting you should say this because I was talking with a road rider a couple of days back looking for advice after taking the recommendations of others (racers) and spending a good load of coin on suspension "upgrades". He now lacks confidence in his bike and just wants it to be the way it was when he purchased it stock. horses for courses

That's a good point... if you use race damping set ups on the road.
My Ohlins cartridges have a quite different valving spec for my predominantly road use of my bike, as opposed to the exact same cartridges that a lot of 06-09 racebikes have in them.
Robert Taylor has revalved my cartridges several times after my feedback, and I believe we have come up with a great "road" spec.
The TTX shock I have is "as delivered" apart from the spring that was changed to suit my weight.
My bike feels a WHOLE lot better than stock in the suspension department

[dipshit]

Well ended up getting a TTX off RT. A rebuilt second-hand unit off a bike that had just finished this season's nationals.

With only one day's riding so far... what a difference! Mid corner bumps aren't such a problem now and you can really get on the gas early and hard in a corner. (well, as hard as a 600 allows anyhow)

Even just adjusting the clickers and bouncing on the seat shows a difference. Before on the standard shock - adjusting the rebound setting didn't make much visible difference to the way the rear end rebounded. It would always rise up slowly and lethargically even when you have been winding the rebound off more and more. One click on the TTX however actually made a visible difference to the speed of the rebound when mucking around in the garage. Got to be a good thing.

Very pleased with the shock from RT and will be turning my attention to the front end next...

[Pussy]

Got the compression piston mod in the TTX on other sem fiddy in our household.
Another VERY happy camper! :)

[dipshit]

Having done a good 6 or 700 ks on the TTX since putting it on a couple of weeks ago, I have continued to be impressed with the improvements it has brought. Like today riding back from Dunedin in light showers with newly wet roads. Was trying to provoke some momentary wheel-spin by gassing it hard over wet bumpy sections of road. But the rear never broke traction and just held its grip and accelerated. The less harshness of the rear and subsequently improved traction has made the bike a lot easier and more forgiving to ride in the wet.

I find it funny how some people think suspension components like a TTX shock is overkill for the street and a rider would only benefit from such if they were pushing hard on a track. Don't know, good suspension is good suspension in my book. :confused:

For about the same money as an aftermarket exhaust and a tune - I reckon I have gotten more bang for my buck this way.

[Pussy]

I find it funny how some people think suspension components like a TTX shock is overkill for the street and a rider would only benefit from such if they were pushing hard on a track. Don't know, good suspension is good suspension in my book. :confused:


Dead right! If you can make the ride safer and more comfy it's a win win situation!

[Shaun]

Well I just rode a GSXR600 today and took high speed adjustment out of the rear ( loosened the adjuster anticlockwise ) and the high speed bump compliance was noticably improved, repeating a riding test over the very same bumps.
Dave Moss would likely have been referring primarily to road race where ride height control and lap times takes precedence over comfort.



Bizzare Robert. I have adjusted 23 of these shocks in the last 30 days, and all the riders noted a huge improvement in the rear, after I closed of the High Speed cuircut ( As I used to do with Ohlin's shocks also every time every where compared all other riders)

[Robert Taylor]

Bizzare Robert. I have adjusted 23 of these shocks in the last 30 days, and all the riders noted a huge improvement in the rear, after I closed of the High Speed cuircut ( As I used to do with Ohlin's shocks also every time every where compared all other riders)

Thats really got to depend on the application and rider stats etc. If the rider is light and rides on a lot of B roads then taking away high speed often works. Trackdays ( an opposite scenario ) then certainly there is a benefit in firmer ride height control, with a loss of comfort over the nastiest bumps. One mans meat is another mans poison, but theres a common scenario, many riders are afraid to go anywhere near the adjusters. Which sometimes is just as well!!!!

[dipshit]

and all the riders noted a huge improvement in the rear, after I closed of the High Speed cuircut

I have often read that Suzuki's shocks typically have weak high speed comp damping.

Dave Moss also quite often suggests closing up high speed comp for better bump compliance even though going that way seems counterintuitive at first... i.e... http://www.ustream.tv/recorded/4985094

[Robert Taylor]

I have often read that Suzuki's shocks typically have weak high speed comp damping.

Dave Moss also quite often suggests closing up high speed comp for better bump compliance even though going that way seems counterintuitive at first... i.e... http://www.ustream.tv/recorded/4985094

Yes that can work, especially for heavier / taller riders doing track days. Its compenasting to a degree for the shim stack opening pressure on the main piston being weak.
But for lighter road riders at median speeds on main roads not neccessarily so. Everyone is different in what they want.

Of course if it does work and works best with the adjuster closed right in then its saying that the main stack needs revalving so that the adjuster can be moved back closer to the middle area of its response range.

[dipshit]

With having both the TTX and a fork revalve the 600 is fantastic now!

The forks are a lot firmer now with far less change of attitude in the front of the bike.
(though at the same time smoother with less harshness over bumps) The bike doesn't feel like it wants to run wide or suddenly tighten its line if you get on or off the gas through a corner. Holds a line with ease.

Before having the forks seen to and just running the TTX... I had reduced compression damping one click from what CKT had set it up on to get a little bit more movement to match what the front was doing I suppose. At the time it felt firmer than the front.

Then yesterday with the reworked forks I tried reducing compression damping a 1/4 turn to see if it would give better bump compliance... but it didn't feel as good in its ability to hold a line like it was on rails. Put compression back to how I had got them from CKT.

So today I increased the compression damping back up the one click on the TTX and bingo!

The 600 is now so incredibly firm in its ride height/attitude that nothing seems to faze it it all. Both ends feel like they are acting as one. At the same time it is so much smoother with far less harshness over bumps than how it was when stock at both ends.

That must be the "firm but compliant" people talk about.

It's an incredible feeling!

[Odakyu-sen]

That must be the "firm but compliant" people talk about.

It's an incredible feeling!

Once you know what good suspension is, you will never go back. It works all the time at all speeds and provides benefits in so many ways.

I believe that's where the manufacturers skimp. Think about it. Everybody wants a more powerful engine or a faster top speed, but not everybody needs a 9.0 Nmm spring in the rear shock. I suspect that the majority of riders really haven't got their heads around the concept of properly set-up suspension.

[dipshit]

I believe that's where the manufacturers skimp. Think about it. Everybody wants a more powerful engine or a faster top speed, but not everybody needs a 9.0 Nmm spring in the rear shock.

But also the manufacturers need to put a bike out the door that could be ridden by someone 50 kg or have two 150 kg people on it two-up and not be a death trap for either extreme and have themselves sued.

That's why it's best to optimise it to your weight alone and actually have the bike handle the way it was intended to.

[Pussy]

That's why it's best to optimise it to your weight alone and actually have the bike handle the way it was intended to.

Ain't that the truth! Best mod to do to a bike.
You can now appreciate what I've been crapping on about!!