sv650 fork TLS/R setting

@ Berlin: yes, I'm running rebound 1 click out from fully in and comp. 1 click in from fully out. I tried a few minutes ago and when I turn rebound 7-8 clicks out, and compress the suspension the bike really bounces back on return, so probably something is wrong. The bike is stable under brakes and normal on entry, but when the bike really digs in to the corner and lean angle rises, it feels like the front is loosing grip/letting go. At first the rear was unstable under acceleration out of corners but after turning rebound and comp. of the rear shock two clicks harder it was better.


The previous owner of the forks phoned back this afternoon with more info. The forks were used on a race TLR and were revalved by Kayaba for that bike, so I'm afraid that means trouble (shimmed way to heavy, heavier bike-> less rebound damping needed?, and more comp. damping needed)

I've been measuring like you asked:

(I weigh 83Kg without gear)

Sag: Front 2,1 cm without rider 3 with me on it
Rear 1,6 cm without 4with me on it (too soft? but it is already wound up pretty hard)

The fork legs (top of legs to middle of spindle) are 71,6 cm
The outer leg tube is 49,5cm
From front wheel spindle to frame head (bottom yoke side) is 48,3 cm
The with between the legs is 21,5 (centre to centre)

Length of the rear shock is 35,8cm.

Is this in the region of your (track)bikes?
And from where to where do you measure rear ride height. (can vary a lot)

Thanks

for pictures:

http://pbmagforum.co.uk/index.php?showtopic=5961&st=0

[fastdruid]

So TLR forks with Ohlins internals, 110 front might have something to do with the front feeling like it wants to tuck.

Druid

yes, turns out (from the tlr owner) its revalved by Kayaba, probably Ohlins internals

last trackdays I've been using 120 front tyre (bt002) and 1cm higher at front to make it less nervous, but on not good surface corners, the problem stayed pretty much the same.

[21QUEST]

Originally Posted by -Trollspeed-

@ Berlin: yes, I'm running rebound 1 click out from fully in and comp. 1 click in from fully out. I tried a few minutes ago and when I turn rebound 7-8 clicks out, and compress the suspension the bike really bounces back on return, so probably something is wrong. The bike is stable under brakes and normal on entry, but when the bike really digs in to the corner and lean angle rises, it feels like the front is loosing grip/letting go. At first the rear was unstable under acceleration out of corners but after turning rebound and comp. of the rear shock two clicks harder it was better.


The previous owner of the forks phoned back this afternoon with more info. The forks were used on a race TLR and were revalved by Kayaba for that bike, so I'm afraid that means trouble (shimmed way to heavy, heavier bike-> less rebound damping needed?, and more comp. damping needed)

I've been measuring like you asked:

(I weigh 83Kg without gear)

Sag: Front 2,1 cm without rider 3 with me on it
Rear 1,6 cm without 4with me on it (too soft? but it is already wound up pretty hard)

The fork legs (top of legs to middle of spindle) are 71,6 cm...72cm
The outer leg tube is 49,5cm
From front wheel spindle to frame head (bottom yoke side) is 48,3 cm
The with between the legs is 21,5 (centre to centre) 21.4cm

Length of the rear shock is 35,8cm.

Is this in the region of your (track)bikes?
And from where to where do you measure rear ride height. (can vary a lot)

Thanks

Now, I'm no expert so only my opinion from my experience...

I've made some correction(in red) to some of your numbers. Fro memory but they are correct.

Springs appears to be in the ball park for your weight so we could take that out of the equation.

From those figures, forks are 2.5cm to 3cm(can't remember the length of the SV forks) shorter than SV forks

Rear Shock(what shock have you got on it again?) is 21mm longer than length of standard SV shock.

As said, if I were you, I'd be looking to get as close as to standard figures and then work from there. I know a lot of folks might say otherwise but 'simples' tends to work for me. Even racers would prefer different set ups.

I've never really liked the feel of the 120/70 myself but with the setup you have now, you don't have much choice anyway. That said, for track days etc, 120/70 wouldn't give the same odd feel as it gives(my opinion) on the road. I found the 120/60 gave a more neutral feel, which I prefer.

Anyhoo, to not digress too much., If the shock is after market and you can lower ride height at back a bit, I'd start from there. Possibly not so good for ground clearance(?) but you just have to bear taht in mind. I'd start with standard length and then go in 5mm 10mm increments.(you can then go 3mm up or down, depending on feedback you get.

Re forks, I know , they have been revalved but I still wouldn't jump straight into speding money on a errr re-revalve lol. If you are having to crank rebound up, you could try a thicker oil than what you have now....be good to know exactly(brand and weight) of ol you have in there. Saves you having to find your own base point.

Thicker oil should give you a bit more rebound before you run out.

Some of the terminology might be slightly misplaced but the core of the reasoning is good....again IMO

Try the simple sthings which shouldn't cost you much money. You might need to call in the experts in the end but you would have learnt something along the way anyways.

I have to repeat again lol, even if you have to call in the experts , choose wisely ....



Cheers
Ben

[yorkie_chris]

Only very slightly thicker oil though, they'll feel harsh as hell if you go for something far thicker.

Try table on here to find a suitable oil http://www.peterverdonedesigns.com/lowspeed.htm

[21QUEST]

Originally Posted by -Trollspeed-

yes, turns out (from the tlr owner) its revalved by Kayaba, probably Ohlins internals

last trackdays I've been using 120 front tyre (bt002) and 1cm higher at front to make it less nervous, but on not good surface corners, the problem stayed pretty much the same.

Re the bit I've highlighted, are the forks not flush with the top yoke?


Cheers
Ben

Originally Posted by -Trollspeed-

@ Berlin: yes, I'm running rebound 1 click out from fully in and comp. 1 click in from fully out. I tried a few minutes ago and when I turn rebound 7-8 clicks out, and compress the suspension the bike really bounces back on return, so probably something is wrong. The bike is stable under brakes and normal on entry, but when the bike really digs in to the corner and lean angle rises, it feels like the front is loosing grip/letting go. At first the rear was unstable under acceleration out of corners but after turning rebound and comp. of the rear shock two clicks harder it was better.


The previous owner of the forks phoned back this afternoon with more info. The forks were used on a race TLR and were revalved by Kayaba for that bike, so I'm afraid that means trouble (shimmed way to heavy, heavier bike-> less rebound damping needed?, and more comp. damping needed)

I've been measuring like you asked:

(I weigh 83Kg without gear)

Sag: Front 2,1 cm without rider 3 with me on it
Rear 1,6 cm without 4with me on it (too soft? but it is already wound up pretty hard)

The fork legs (top of legs to middle of spindle) are 71,6 cm
The outer leg tube is 49,5cm
From front wheel spindle to frame head (bottom yoke side) is 48,3 cm
The with between the legs is 21,5 (centre to centre)

Length of the rear shock is 35,8cm.

Is this in the region of your (track)bikes?
And from where to where do you measure rear ride height. (can vary a lot)

Thanks

This is curvy, right?
Sound like your oil is bad and/or high speed rebound is not right (shim stack).
When you measured sag on front did you calculate average for stiction? If not you need to. Good spring for your weight would be .90.
Shock is to long, don't go over 355mm, somewhere around 350-355 is good range. If your spring is wound up it is way to soft, you need around 115Nmm.

[fastdruid]

OK, some dimensions for you

Yoke fork Centres
TL1000S/R/hayabusa - 214mm
GSXR1000K1-8/GSXR600/750Y-K7 - 207mm

Yoke top fork dia
All - 50mm

Yoke bottom fork dia
TL1000S/R/hayabusa - 55mm
GSXR1000K1-6 - 54mm
GSXR1000K7-8 - 56mm
GSXR600/750Y-K5 - 54mm
GSXR600/750K6-K7 - 53mm

Yoke Offset
TL1000S/R/hayabusa - 32mm
GSXR1000K1-4 - 32mm
GSXR1000K5-6 - 30mm
GSXR1000K7-8 - 28mm
GSXR600/750Y-K3 - 32mm
GSXR600/750K4-5 - ??mm
GSXR600/750K6-K7 - 30mm

fork Length from Spindle centre to top of fork cap
TL1000S - 732mm
TL1000R - 717mm
Hayabusa - 725mm
GSXR1000K1-2 - 726mm
GSXR1000K3-8 - 720mm
GSXR600/750Y-K3 - 720mm
GSXR600/750K4-5 - ??mm
GSXR600/750K6-7 - 738mm

I have my hayabusa forks flush, your forks are ~8mm shorter.

Druid

Originally Posted by fastdruid

GSXR600/750K4-5 - ??mm

722mm
Remember this measurements can be different for few mm depending on preload.