Stock GSX-R 600 k8 suspension help

**dipshit** · 25th August 2009, 20:27

Originally Posted by 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.

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** · 26th August 2009, 09:31

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** · 26th August 2009, 17:59

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** · 26th August 2009, 19:40

Originally Posted by dipshit

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** · 26th August 2009, 20:03

Originally Posted by Pussy

Probably the best bet, dipshit.

I hadn't played with the high speed damping much because in the onthethrottle 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** · 1st September 2009, 09:23

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** · 1st September 2009, 18:23

Originally Posted by 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!]

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** · 1st September 2009, 18:35

Originally Posted by 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!]

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** · 1st September 2009, 18:44

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** · 1st September 2009, 19:57

Originally Posted by Pussy

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** · 2nd September 2009, 11:49

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** · 2nd September 2009, 15:21

Originally Posted by 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.

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** · 3rd September 2009, 16:58

Originally Posted by dipshit

I hadn't played with the high speed damping much because in the onthethrottle 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** · 3rd September 2009, 21:05

Originally Posted by Robert Taylor

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.