Shock and fork shimming and valve drilling

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Shock and fork shimming and valve drilling

Post  Achile on Fri Feb 15, 2013 8:00 pm

Hey guys!


I'm thinking of tampering with the suspension. I do a lot of fast trail riding and technical trails with some KTM lovers and my arms are killing me. I feel every rock and bump and want a change. I weigh about 174 lbs, so the stock fork springs are ok, and run 2.5w motorex fork oil. I'm leaning twards the trail setup(super plush). What do you guys think?? StirPot
Bruce said to get rid of the 0.4x10 mm shims on the compression stack...or so I think. In this setup, i just have to move a 21 mm shim from the stock rebound stack to the compression and ??remove the 0.4x10?? shim.
Any thoughts???


Burce's rear shock page is unavailable...any suggestions?



Best regards,
Alex

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Re: Shock and fork shimming and valve drilling

Post  Mad Frosty on Fri Feb 15, 2013 11:43 pm

Send it to precision concepts or racetech , tell them what you want and be happy , naughty
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Re: Shock and fork shimming and valve drilling

Post  BuRP on Sat Feb 16, 2013 7:00 am

Achile, Pig & Romania..... you must be the same on AdvRider!!!
Welcome here too bru!

Before you send stuff over the waters for a good-but-dear (PC) setup do the Borynack mods, front and rear, and do them yourself! Oh, and do them as per his book, why reinvent your own wheels?
Cheap enough, you will learn something too, and the results apparently are stunningly good !!
Crypto666 (friend on Adv) recently did the shock, and reported he wished he had done this the day he got the bike, and recommends anyone does this mod - including the front but he had done that early already.
I still have not touched mine (lack time Neutral) but I will do these mods as soon as I see a gap - and then also will put in the springs which are lying in wait here.

The PigPen's pages are on&off available, so trial&error is the way to go, add some persistance. But if you don't come right PM me with an email addy and I'll throw you what you need, got this stuff on my PC here.
Goodluck, and do report back when you've finished raving about how good it is to your local friends please?
Oh, and screw orange too, go give them hell with your new setup!!
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Re: Shock and fork shimming and valve drilling

Post  BuRP on Sat Feb 16, 2013 7:06 am

And that, Maddy, you should keep in mind too!
I know PC has a good rep, but do the above mods first - then complain, or throw money over a cliff or whatever, it is yours anyway Wink
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Re: Shock and fork shimming and valve drilling

Post  Achile on Sat Feb 16, 2013 8:07 am

BuRP wrote:Achile, Pig & Romania..... you must be the same on AdvRider!!!
Welcome here too bru!

Before you send stuff over the waters for a good-but-dear (PC) setup do the Borynack mods, front and rear, and do them yourself! Oh, and do them as per his book, why reinvent your own wheels?
Cheap enough, you will learn something too, and the results apparently are stunningly good !!
Crypto666 (friend on Adv) recently did the shock, and reported he wished he had done this the day he got the bike, and recommends anyone does this mod - including the front but he had done that early already.
I still have not touched mine (lack time Neutral) but I will do these mods as soon as I see a gap - and then also will put in the springs which are lying in wait here.

The PigPen's pages are on&off available, so trial&error is the way to go, add some persistance. But if you don't come right PM me with an email addy and I'll throw you what you need, got this stuff on my PC here.
Goodluck, and do report back when you've finished raving about how good it is to your local friends please?
Oh, and screw orange too, go give them hell with your new setup!!


Yeah, that's me Smile)). Wassup, ma' piggy bos'???
I'll do it myself and I'm thinking of going on the super plush trail riding setup or the serious riding. Can anyone tell me if I should use 2 0.15x21 shims on the rebound stack or loose them? I have stock springs and the site says 2 0.15x21mm shims if i'm running 0.45 springs(+1 if I have 0.47).

(6) .10mm X 21mm
(1) .10mm X 13mm
(2) .15mm X 21mm**
(1) .10mm X 20mm
(1) .10mm X 18mm
(1) .10mm X 16mm
(1) .10mm X 14mm
(1) .10mm X 12mm
(1) .10mm X 11mm


** this is for .45kg/mm springs add another .15mm X 21mm for .47kg/mm springs



So???
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Re: Shock and fork shimming and valve drilling

Post  Hew on Sat Feb 16, 2013 9:21 am

I left the shims as they. Mainly due to being too impatient to find a source of shims to swap around.
Dived in and drilled the valves as per borynacks article. I found this made a hell of a difference and have not bothered to play with the shims since.
It was always good at soaking up the big hits but when riding over loose rocks I was struggling and failing to keep it pointing in the direction I wanted to go.
Now the harder I ride it the better it gets.
Note that the valves can be a bit brittle and if the drill snags it could chip the face of the valve, try to use a drill stand. Failing that take care to keep the hand drill straight. Also I would also only tighten up the nut on the shim stack to what feels right. The torque setting seemed high to me for such a small aluminum thread, you are using loctite anyway.

Best mod I have ever done to any bike and the best party is it cost f all rider
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Re: Shock and fork shimming and valve drilling

Post  Achile on Sat Feb 16, 2013 10:57 am

Hew wrote:I left the shims as they. Mainly due to being too impatient to find a source of shims to swap around.
Dived in and drilled the valves as per borynacks article. I found this made a hell of a difference and have not bothered to play with the shims since.
It was always good at soaking up the big hits but when riding over loose rocks I was struggling and failing to keep it pointing in the direction I wanted to go.
Now the harder I ride it the better it gets.
Note that the valves can be a bit brittle and if the drill snags it could chip the face of the valve, try to use a drill stand. Failing that take care to keep the hand drill straight. Also I would also only tighten up the nut on the shim stack to what feels right. The torque setting seemed high to me for such a small aluminum thread, you are using loctite anyway.

Best mod I have ever done to any bike and the best party is it cost f all rider


I'll check the shimming diagrams again and check the differences between the stockie and the serious riding setups...and make up my mind after that. I'd like to do it properly, if I do it.
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Re: Shock and fork shimming and valve drilling

Post  BuRP on Sat Feb 16, 2013 2:43 pm

NICE avatar Hew!

You see Mauser, pigs can swim


Hew, your "Now the harder I ride it the better it gets" I've heard before, from others. Darn, I should force myself to do this to mine soon.
Oh, you forgot to type 'uck' in your closing line


Achile,

why not PM Crypto666 on AdvRider? He does know about the shims and will happily tell you. The stack does make a difference so do all as er mentioned - but it's good to know that only drilling the valves already makes a big-enough difference.
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Re: Shock and fork shimming and valve drilling

Post  Mad Frosty on Sat Feb 16, 2013 3:02 pm

I wish i have more time , i always end up paying someone to do the big jobs ,
btw i like to farkle with the bike .
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Re: Shock and fork shimming and valve drilling

Post  Achile on Sat Feb 16, 2013 4:10 pm

Sent a PM...waiting for reply BRP smile
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Re: Shock and fork shimming and valve drilling

Post  Mur on Mon Feb 18, 2013 2:45 am

Hew wrote:I left the shims as they. Mainly due to being too impatient to find a source of shims to swap around.
Dived in and drilled the valves as per borynacks article. I found this made a hell of a difference and have not bothered to play with the shims since.
It was always good at soaking up the big hits but when riding over loose rocks I was struggling and failing to keep it pointing in the direction I wanted to go.
Now the harder I ride it the better it gets.
Note that the valves can be a bit brittle and if the drill snags it could chip the face of the valve, try to use a drill stand. Failing that take care to keep the hand drill straight. Also I would also only tighten up the nut on the shim stack to what feels right. The torque setting seemed high to me for such a small aluminum thread, you are using loctite anyway.

Best mod I have ever done to any bike and the best party is it cost f all rider
Here's where I got my shims from. They shipped them out fast and didn't charge an arm and a leg for them. I think most come in a pack of 2.. http://racingsuspensionproducts.com/shim/shim.html
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Re: Shock and fork shimming and valve drilling

Post  DSA on Mon Feb 18, 2013 12:34 pm

Achile wrote:
BuRP wrote:Achile, Pig & Romania..... you must be the same on AdvRider!!!
Welcome here too bru!

Before you send stuff over the waters for a good-but-dear (PC) setup do the Borynack mods, front and rear, and do them yourself! Oh, and do them as per his book, why reinvent your own wheels?
Cheap enough, you will learn something too, and the results apparently are stunningly good !!
Crypto666 (friend on Adv) recently did the shock, and reported he wished he had done this the day he got the bike, and recommends anyone does this mod - including the front but he had done that early already.
I still have not touched mine (lack time Neutral) but I will do these mods as soon as I see a gap - and then also will put in the springs which are lying in wait here.

The PigPen's pages are on&off available, so trial&error is the way to go, add some persistance. But if you don't come right PM me with an email addy and I'll throw you what you need, got this stuff on my PC here.
Goodluck, and do report back when you've finished raving about how good it is to your local friends please?
Oh, and screw orange too, go give them hell with your new setup!!


Yeah, that's me Smile)). Wassup, ma' piggy bos'???
I'll do it myself and I'm thinking of going on the super plush trail riding setup or the serious riding. Can anyone tell me if I should use 2 0.15x21 shims on the rebound stack or loose them? I have stock springs and the site says 2 0.15x21mm shims if i'm running 0.45 springs(+1 if I have 0.47).

(6) .10mm X 21mm
(1) .10mm X 13mm
(2) .15mm X 21mm**
(1) .10mm X 20mm
(1) .10mm X 18mm
(1) .10mm X 16mm
(1) .10mm X 14mm
(1) .10mm X 12mm
(1) .10mm X 11mm


** this is for .45kg/mm springs add another .15mm X 21mm for .47kg/mm springs



So???

Leave it as is, you should have enough adjustment with the clickers to cover the additional spring energy.

now if you went to a .49 or .52kg then throw in a extra shim, even then a .10x21mm
the .15 is 3.4 times stronger than a .10

http://www.mx-tech.com/articles/File/Shim_Conversion.pdf

Hope this helps
Allen
www.dualsportarmory.com
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Re: Shock and fork shimming and valve drilling

Post  BuRP on Mon Feb 18, 2013 5:39 pm

DSA,

no bragging here but my mathematics are excellent.
Helps zero though, as I haven't got the foggiest how these shims work, what they do, the technical principle I mean.
Explain a bit?
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Re: Shock and fork shimming and valve drilling

Post  Achile on Mon Feb 18, 2013 7:12 pm

Think of the shims as a ball valve. On/off. The fork plunges, the ball rises and the oil rushes through the holes of the valve. When it goes back, the ball dosen't let the oil go back through the compression back and there is only one way to go...rebound stack. Ok. This is the principle.
The shims are...flexible. The fluid rushing through the holes of the valve flexes the shims. The stiffer the stack, the more force needed to flex them(bigger bump). The flexing of the shims controls the oil flux, thus making the fork stiffer or softer.

>this is what I understod<
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Re: Shock and fork shimming and valve drilling

Post  BuRP on Tue Feb 19, 2013 4:37 pm

Thanx, that makes sense.... but not so the movement to smaller diameters then, or worse, going back to bigger one's? Unless that is very fine tuning ?
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Re: Shock and fork shimming and valve drilling

Post  Achile on Tue Feb 19, 2013 6:06 pm

so... I went with the trail stack.

1) you don't need any special tools
2) you can do the mod whitout taking the fork apart
3) it's damn easy


Step 1: turn the fork upside down and grip it in a vise; put something underneath the fork and compress it; take out the compression stack
Step 2: drain the oil
step 3: unscrew the fork cap, take out the spring, take out the rebound stack.
step 4: do what you need to do with the stacks and drill the valve
step 4: put back the top cap, put the fork back to the vise, measure 637 cmc of oil, put it into the fork, compress the fork and put in the bottom cap.

There you have it...no need for special DIY tools Bump
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Re: Shock and fork shimming and valve drilling

Post  Hew on Tue Feb 19, 2013 8:27 pm

Nice one.
Dont forget you still have all the clickers to play with and adjust.
You will notice a hell of a difference and the bike will be a lot nearer to what you have always wanted.
Enjoy. Bananatool
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Re: Shock and fork shimming and valve drilling

Post  Achile on Tue Feb 19, 2013 8:36 pm

Hew wrote:Nice one.
Dont forget you still have all the clickers to play with and adjust.
You will notice a hell of a difference and the bike will be a lot nearer to what you have always wanted.
Enjoy. Bananatool

Off the bench settings are: 6 on the compression and 11 on the rebound. I'll play with them when I'll hit the dirt. I used loctite on the rebound and compression stacks. The 30 lbs f measure up with 3 Nm...a bit hard to measure with a torque wrench. My smallest went up from 7 NM. I tightened them to 7 and went back a litle until they felt right. Used a hammer and a small cizle secure the thread and put in loctite. Hope it's ok.
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