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YZ125 2008 woods fork revalving

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Hi!

I own a (Euro model) 2008 YZ125 and I am happy with the stock suspension generally except in one area: sharp stones and roots (especially when wet) where the bike has the tendency to deflect. I use the stock springs because I weigh 84 kg with gear and I have removed 20ml of oil from the outer chamber (stock is 335ml, now 315ml). It is not bad but after I drove a KTM EXC125 2012 model and a Husqvarna WR125 2012 during an organised demo ride today I am spoiled and I decided that I have to revalve my forks. The KTM was super plush in wet rocks where the Husky was firmer. I know I can get the YZ forks as good as the others.

I have some reshimming experience from an open chamber Ohlins 46mm fork and I know how to bleed the KYB fork. If the stock YZ fork base valve and midvalve stack is something like this (what I found here about other Yamaha SSS KYB forks) :

32-0.11 x 16

30

28

26

24

22

20

18

16

14-0.25 (pivot-base)

Bleed:

11-0.25 x 5

14-0.11

16-0.11

18-0.11

20-0.11

22-0.11

Mid:

20-0-11 x 4

18

16

14

12-0.15

11-0.30 x 2

17-0.30 x 2

Will I make it too soft with the following arrangement?

32-0.11 x 10

30

27

24

21

18

15

12-0.25 (pivot)

Bleed stack the same

Mid:

20-0.11 x 3 (1 out)

18

16

14

12-0.15

11-0.30

17-0.30.

And then to adjust bottoming resistance with oil volume. What do you think? It it too much to remove that many face shims while changing the high speed stack? I want the fork to stay high in the stroke and be more compliant for square edge stones and roots. I think a 2 stage stack is not sufficient.

I will be very thankful for your replies and help.

Leon

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Is it too much to remove that many face shims while changing the high speed stack?

I wouldn't change the high speed stack. though you may think less shims there results in less high speed damping - it doesn't. to be correct, it does, but it also has less low speed damping. instead I would only remove face shims.

the shims you remove in the mid valve results in 0.7 more float. is this desired?

I'm no expert in woods float...

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These are stock stacks

bv

32-0.11*16

30-0.11*1

28-0.11*1

26-0.11*1

24-0.11*1

22-0.11*1

20-0.11*1

18-0.11*1

16-0.25*1

11-0.25*5

14-0.11*1

16-0.11*1

18-0.11*1

20-0.11*1

22-0.11*2

mid

20-0.11*4

18-0.11*1

16-0.11*1

14-0.11*1

12-0.15*1

11-0.30*2

17-0.30*2

5.3 mm slide collar (float about 0.25)

8-0.15*1

You are going to make the fork too soft. By removing one face shim from mid will make a huge difference...but it makes the fork dive more and you have to do something to rear shock to compansate this and keep the balance. When the fork dive too much it may feel harsh and unpredictable.

4mm smaller clamp shim on bv will also make same effect and so do that face shim remove.

Jusa

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Thank you so much for the replies!

Ok, I try to understand the consequences. So, is it ok to just touch the bv only? I know the effect of too soft fork compared to shock. Last Saturday I opened 2 clicks the compression and the fork was harsh through stones and roots. From experience I feel that the shock is way more adjustable through the clickers than the fork. I can make it softer. Now I have it like "as hard as I can stand it and still be ok through rocks".

Will then this arrangement be ok in the BV stack?

32-0.11 x 16

30

27

24

21

18

16-0.25 (pivot).

It's a give and take situation. I think that the face shims keep the fork up in the stroke. Isn't it so? One problem is that I need to order the new high speed shims from somewhere. Years ago I ordered from racingsuspensionproducts.com . Do you know Jusa of any place in Finland I can buy individual shims and not big packages?

I was happy to realise that the YZ is up there with the other brands, with (in my opinion) better all around engine with the SFB 7oz weight I added recently and better more natural ergonomics. If I get the fork to work 10-15% better through rocks and roots without losing the great characteristics everywhere else, then I will be very happy. Already now I win some guys from the B class whenever I race enduros and most of the guys from the C class, depending on how nasty the paths are. I write all these things so you understand better what I am searching for.

Thank you again for your help!

Leon

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I think that the face shims keep the fork up in the stroke. Isn't it so? One problem is that I need to order the new high speed shims from somewhere.

no! you look at the shims as individual devices, which isn't true. you don't even have a crossover there, so every part of the stack controls every speed range.

I guess you don't believe that because when they are called HS shims they have to control the HS only.

I try to explain: if you want to compare a stack with and without HS shims, you have to replace the HS shims with a determined number of face shims.

both stacks will have about the same amount of low- and midspeed damping, but the stack with the pyramide has less highspeed damping. thats why they are called HS shims.

well, the result in changing HS shims instead of LS shims will differ only minimal, and is the wrong way IMO, but if this is what you want to do, it will work, too.

if I don't have the diameter shim I need, I grind it down...

Edited by kawamaha

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leon,

I question the bleed stack on the bv for a 125. Also, IMO pulling a 20, increase the float on the mid would help a lot.

I would try those since you don't need to buy shims. Maybe invert the bleed stack.

jw

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Thank you so much for the replies!

Ok, I try to understand the consequences. So, is it ok to just touch the bv only? I know the effect of too soft fork compared to shock. Last Saturday I opened 2 clicks the compression and the fork was harsh through stones and roots. From experience I feel that the shock is way more adjustable through the clickers than the fork. I can make it softer. Now I have it like "as hard as I can stand it and still be ok through rocks".

Will then this arrangement be ok in the BV stack?

32-0.11 x 16

30

27

24

21

18

16-0.25 (pivot).

It's a give and take situation. I think that the face shims keep the fork up in the stroke. Isn't it so? One problem is that I need to order the new high speed shims from somewhere. Years ago I ordered from racingsuspensionproducts.com . Do you know Jusa of any place in Finland I can buy individual shims and not big packages?

I was happy to realise that the YZ is up there with the other brands, with (in my opinion) better all around engine with the SFB 7oz weight I added recently and better more natural ergonomics. If I get the fork to work 10-15% better through rocks and roots without losing the great characteristics everywhere else, then I will be very happy. Already now I win some guys from the B class whenever I race enduros and most of the guys from the C class, depending on how nasty the paths are. I write all these things so you understand better what I am searching for.

Thank you again for your help!

Leon

That stack looks better. You can also remove 2 or max 3 face shims from stock bv or soften the mid or take one shim out of bleed stack and use it as a cross over...many ways if you don't have enough extra shims.

You can't find any shop here in Finland who sells shims, not even tuners because they need them, but I order shims from MX-Tech and Technical touch.

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leon,

I question the bleed stack on the bv for a 125. [...] Maybe invert the bleed stack.

jw

I ride a 125 YZ and it also got a bleedstack! But I also disabled it.

Sometimes stock is weird I guess...

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Thank you all again for the replies! All the time I learn something new from you. Because I don't have spare shims I will try first to remove one face shim from the mid as suggested and invert the bleed stack. This Saturday we have a 2 hr cross country practice race in sand so I will try this change next week. I will put the oil volume back to stock spec at 335 ml to help resist any possible excessive blow through the stroke. I need to test this to relax my mind before my arranged knee surgery in November. I can somehow still ride because the Asterisk knee braces hold my knee tightly...

It was amazing how soft the KTM 125 2012 was and could absorb any rock perfectly. The kind of ride that keeps you fresh all day. The fork did dive a lot during hard braking but still it was manageable. I don't think that the YZ will get that soft with one shim removed from mid but we will see.

The reason that I want to try myself is that I was behind and watching one famous professional do the SSS KYB forks of my previous YZ250 2T 2008. He touched every possible shim stack in the fork and the result was that after months when I realised that the fork is too soft I added lots of oil (per his advice) several times and finally the fork was still ok in the first part of the stroke and awfully hard at the beginning of the 2nd part of the stroke. I don't want to go this route again.

Thank you all for the replies!

Leon

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no! you look at the shims as individual devices, which isn't true. you don't even have a crossover there, so every part of the stack controls every speed range.

Right - I think you need to really go for broke and install a 2-stage stack. I generally valve for low-speed in the normal range for my weight, but drastically soften the high-speed stacks. New England rocks and all...

JayC

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Hi!

I checked all clicker settings for the fork and shock before tomorrows practice in sand and the low speed adjuster was at 10 out (for the last months) instead of 13 out as suggested by the manual. I think this connects to the harshness I felt when i tried to soften 2 clicks the fork compression. Too hard shock compared to fork. That's the result of testing things and not keeping notes of the settings. I put it to 13 out and the fork to stock clicker settings for reb and comp (and 20ml less oil in outer chamber). The high speed adjuster at the back is at 1/6 turn out from stock setting. I didn't have with me a second person to measure sag but I will do it soon. Months ago when I adjusted it was something between 100 and 105 mm. I might not need a fork revalve but because is time to change the inner chamber's oil I might try it next week.

Thank you all again,

Leon

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Those Yamaha set ups are on soft side from factory. I had stiffer set ups in 2008 for enduro, so I think you don't have to do big changes.

I suggest to run 95-100mm race sag and fork tubes stock height. If your shock is modified you can't follow your manual anymore about the clicker settings.

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Hi!

Shock is not modified. On Saturday it was ok during the 2hr practice in sand. To keep speeds low we had to cross some very tight woods sections that got rough from the beginning due to wet conditions from previous rains. Some stones appeared in these tight sections. It was a short lap including half sand MX track and the tight sections. Bike definitely was more balanced. One of the very good finnish A class MX drivers (M. Lehto) had a fight through out the race with another young gun and both managed 35 laps. I managed 29 with one fuel stop so the bike was not bad at all with the clicker settings I listed above. Also, I didn't use 5 cm of the fork travel even if there was one rough whoop section I was full on in 3rd gear and one "smooth" whoop at the landing point of a small tabletop jump.

I searched a bit more about the YZ 125 and it seems that the bleed stack was inverted in 2006 resulting in a stiffer fork than in 2008 even though the older bike had slightly softer springs. So I think I shouldn't touch the midvalve. Maybe it's enough to test the different HS shims I suggested plus remove 2 face shims as you suggested (and fine tune with oil volume). I am just asking for 10-15% better fork through rock gardens and wet roots. Now I need to order some shims from MX-Tech...

I will let you know of the test results!

Leon

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I have an 06 yz125 and removed a lot of face shims, I have 5 then a 22x.01 crossover and 5 more face shims and the rest of the stack stock. This works decent for woods, not perfect but you don't get out of control when you hit a rock. I didn't touch the midvalve although if I was to do it again I would probably take out on face shim on the mid and run 8 face shims on the base then crossover and 3-4 more. I would recommend you removing more than 1 face shim, you really aren't going to feel much difference if you only remove 1.

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I have an 06 yz125 and removed a lot of face shims, I have 5 then a 22x.01 crossover and 5 more face shims and the rest of the stack stock. This works decent for woods, not perfect but you don't get out of control when you hit a rock. I didn't touch the midvalve although if I was to do it again I would probably take out on face shim on the mid and run 8 face shims on the base then crossover and 3-4 more. I would recommend you removing more than 1 face shim, you really aren't going to feel much difference if you only remove 1.

You don't have enough damping with 5 face and cross over. IMO it's dangerous to ride too soft set up.

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Hi!

Shock is not modified. On Saturday it was ok during the 2hr practice in sand. To keep speeds low we had to cross some very tight woods sections that got rough from the beginning due to wet conditions from previous rains. Some stones appeared in these tight sections. It was a short lap including half sand MX track and the tight sections. Bike definitely was more balanced. One of the very good finnish A class MX drivers (M. Lehto) had a fight through out the race with another young gun and both managed 35 laps. I managed 29 with one fuel stop so the bike was not bad at all with the clicker settings I listed above. Also, I didn't use 5 cm of the fork travel even if there was one rough whoop section I was full on in 3rd gear and one "smooth" whoop at the landing point of a small tabletop jump.

I searched a bit more about the YZ 125 and it seems that the bleed stack was inverted in 2006 resulting in a stiffer fork than in 2008 even though the older bike had slightly softer springs. So I think I shouldn't touch the midvalve. Maybe it's enough to test the different HS shims I suggested plus remove 2 face shims as you suggested (and fine tune with oil volume). I am just asking for 10-15% better fork through rock gardens and wet roots. Now I need to order some shims from MX-Tech...

I will let you know of the test results!

Leon

You have now 4.1N fork springs (stock) you can also go one step softer 4.0N springs

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Jusa, with the stock stack on the midvalve which is meant for mx, you can go very soft on the basevalve for a woods setup. I agree its much too soft for mx but for slamming boulders it works fairly good.

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Jusa, with the stock stack on the midvalve which is meant for mx, you can go very soft on the basevalve for a woods setup. I agree its much too soft for mx but for slamming boulders it works fairly good.

I have had 2008 yz 125 and 250. Both bikes have excatly same shim set ups.

I rode enduro (with lot of rocks and roots here in Finland) and I had stiffer shim set ups on both ends. When it was very slippery and muddy conditions I went one step softer fork springs and slightly softer shim set ups.

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Hi again!

I ordered some odd size shims on Monday in order to change the HS taper. I think it will be enough to be more compliant in small-mid size sharp rocks and roots without losing the good characteristics in other sections. On bigger and smoother rocks I have no problems. There is so much sand here in Finland that if you get a fork perfect for rocks and roots probably it's not good in the sand. Plus, there is usually part of an MX track in some test in an enduro race, so the fork needs to be a good compromise for everything.

The bv stack will be:

32 x 16 (at first I won't remove anything from here)

29

26

23

20

18

16-0.25 (base).

I made similar changes to an Ohlins 46 fork advised by KTM-Lew here and the change was great.

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with 16 face shims i dont see changing the taper will have any real effect.

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