no variation in rebound (Shiver 45)

[Klausen]

1, 22x1.0
2, 12x1.0
3, 20x1.0
4, 12x1.0
5, 17x1.0
6, 16x1.0
7, 14x1.0
8, 13x1.0
9, 12x1.0

Hi Nick,

is this stack not to stiff in high speed damping?
Because you stack is very thin and the base shim can't move very much and stops early.

I work for a German company called Klaus multiparking, any connection?

no connection sorry


Now I use Motul expert fork oil mixed 5W and 10W 1:1.
I feel more rebound. But I will test it more on the weekend.
And I triple up the base face shim. Low Speed damping is stiffer may be quadruple up.

I ride no cross tracks.
I ride enduro competition with obstacles, hard ground and also stones. Sometimes also sand tracks. Here I need more low speed dumping.

Is there anywhere a explanation for shim stacks.
For examble what happens when I make the stack thinner or thicker?

 

[nick790]

Hi Nick,

is this stack not to stiff in high speed damping?
Because you stack is very thin and the base shim can't move very much and stops early?

I think you may be right, I'm still fine tuning things
This will be my next step.

 

[moto9]

I think you may be right, I'm still fine tuning things
This will be my next step.

I'm running 3w, I like the compression action, specially on the small square stuff, but the rebound needs a stiffer H/S stack arrangment...I'm getting some pogo on the bigger hits.
Next time in I should have it pretty close.

 

[Klausen]

the rebound isn´t enough

actual stack Marzocchi 2006

21 x 0,1
21 x 0,1
19 x 0,1
19 x 0,1
18 x 0,1
17 x 0,1
15 x 0,1

I use Motul expert Oil 5W /10W mixed 1:1 (26,9 reported cst@40C° [centistokes])
(for your info genuine Marzocchi original 7,5 W (26,10 reported cst@40C° [centistokes]))
air 135mm a little bit to much
preload 3mm
4,5 N/mm springs

may be I need a 22x0,1 face shim??

 

[Klausen]

Yesterday we were on the sand track,after them I tested the reboundscrew again.
No variation (open/close) when I push the fork and release.
Is this normal that the L/S rebound is so soft.
When I rode on the track it feels good
May be the H/S rebaound is better?

actual stack Marzocchi 2006

22 x 0,1
21 x 0,1
19 x 0,1
19 x 0,1
17 x 0,1
17 x 0,1
15 x 0,1

I use Motul expert Oil 5W /10W mixed 1:1 (26,9 reported cst@40C° [centistokes])
air 125mm a little bit to much
preload 5mm
4,5 N/mm springs



MV


15 x 0,3
15 x 0,3
22 x 0,3
11 x 0,2

Do this MV (bleed shim) also affect the rebound

 

[nick790]

You should feel a difference by just pushing the forks down.
The MV bleed shim shouldn't affect the rebound unless it's not letting any oil through at all. Is the seal ring on the rebound piston ok?

I would have thought you would have plenty of rebound damping with this set up

 

[GMP]

The MV bleed shim shouldn't affect the rebound unless it's not letting any oil through at all

This is incorrect. The MV functions like a check valve in the rebound direction. If there is bleed from a shim spacing the face shim off the piston, or from a shim smaller in dia than the piston exposing some port area, you have less rebound control and the low speed adjustment (clicker) has little effect.

I beleive I suggested to you in the other thread to remove the 11mm bleed shim on the MV stack before you do anything else.

 

[nick790]

This is incorrect. The MV functions like a check valve in the rebound direction. If there is bleed from a shim spacing the face shim off the piston, or from a shim smaller in dia than the piston exposing some port area, you have less rebound control and the low speed adjustment (clicker) has little effect.

I beleive I suggested to you in the other thread to remove the 11mm bleed shim on the MV stack before you do anything else.

Of course you are correct, sorry must have been late when I wrote that

I have a similar stack to this but with no bleed shim on the MV, I have plenty of rebound damping.

What affect does a bleed shim have on the check valve MV? Other than possibly messing up your rebound.

 

[moto9]

This is incorrect. The MV functions like a check valve in the rebound direction. If there is bleed from a shim spacing the face shim off the piston, or from a shim smaller in dia than the piston exposing some port area, you have less rebound control and the low speed adjustment (clicker) has little effect.

I beleive I suggested to you in the other thread to remove the 11mm bleed shim on the MV stack before you do anything else.

Was that some kind of mistake or off-thinking by the Marz factory...why would anyone place a bleed shim on the MV?
Adding more float would accomplish the same thing without sacrificing bleed off from the rebound circuit.

 

[GMP]

Moto9,

If its a mistake its been one for three years as my '07 was the same. I was surprised that the fork worked stock, but I didn't ride it initially in a situation that would exploit that flaw. BTW, GasGas specs the valving, and you would think that if it was a mistake they woukd have caught it. Crazy idea for sure.

 

[bchatt]

Moto9,

Crazy idea for sure.

I suspect the same person was responsible for airbox, seat and radiator attachment design on the '07. In fact, due to the multi-tasking ethos of the GasGas factory, this persons other role was that of Chief purchasing officer. He mistakenly ordered 426 tons of 3/4 inch wood screws and 188,976 11mm shims, and, well, he had to use them somewhere to hide his cock-up

 

[moto9]

I suspect the same person was responsible for airbox, seat and radiator attachment design on the '07. In fact, due to the multi-tasking ethos of the GasGas factory, this persons other role was that of Chief purchasing officer. He mistakenly ordered 426 tons of 3/4 inch wood screws and 188,976 11mm shims, and, well, he had to use them somewhere to hide his cock-up

That's funny

 

[Klausen]

I beleive I suggested to you in the other thread to remove the 11mm bleed shim on the MV stack before you do anything else.
04-26-2010 06:48 PM

Yes you do and overread this. Sorry.
This was your post.

For a properly functioning checkplate setup just remove the 11mm shim. For a true MV, you would reduce the float and use a thinner face shim like a 22x.15, with a small stack behind it. This can introduce a lot of compression issues if not right. If your not experienced I would suggest getting rid of the 11mm shim, and fixing the rebound as discussed before. The fork should work well like this. Once the main problems are solved then experiment with the MV.

Ok I remove this f... bleed shim.
How should I reduce the float with more shims above the 22x15.
which small stack?
What is your recommendation?

 

[Klausen]

OK now I remove the 11x0,2 MV Bleed shim
and replace the 22x0,3 with 22x0,15.
And stiffen up the Rebound.

15x0,2
15x0,3
15x0,3
22x0,15
Piston
22x0,1
22x0,1
19x0,1
19x0,1
18x0,1
17x0,1
15x0,1
13x0,1

After assembling I thought it works.
Outside of the bike I push the fork down and feel a rebound.
When I close the rebound screw full I hear the oil flow through the piston.

Then I make a short ride.
I go over my test bumps , very nice I thought.
But after 10 times the rebound become less.
When I close the rebound screw full I hear not very much.
I don't know what is the reason.
Where is the leak?
I think the comp works better.
I don't change any seal or bushing.

 

[nick790]

There has been a couple of people with this problem now, it might be a good idea to change the seal on the rebound piston.

I'm going to replace mine the next time it's apart, just in case the same happen to mine, now i'v got then right I don't want it to mess me about.

 

[Klausen]

There has been a couple of people with this problem now, it might be a good idea to change the seal on the rebound piston.

I think this is a piston ring with teflon, mine looks very good.
The teflon surface has no obvious injuries.

 

[nick790]

It's the only place you could be loosing your damping. There very cheep.
It's the last thing you can do, worth it for peace of mind?

 

[darren]

Rebound piston ring ha there like rocking horse poo.

Marzocchi 4 weeks
Gas Gas uk wont order untill end of six day trial then poss couple weeks.
Gas Gas Germany wont post to uk.
Dr shox has none in stock.
K tek has none in stock
Go fasters have none

Still got the same problem with mine.

 

[Klausen]

I think after I rode the fork in a 4h race the rebound becames more.
May be the piston ring clearance becomes closer.
And I believe you can't feel the change of shims very much when you push and release the fork. The movement is to slow and the bleed hole in the piston to great to move the stack. Right?

The feeling in fast hard ground corners becomes much better(the front don't sink too much or higher in the stroke), also I can go slippy grass corners much faster with a better feedback from the front wheel.
But the forks feels still harsh on brake Bumps.
I don't know why, my be to soft in high speed dumping and to much rebound or to stiff high speed dumping.
How can I invastigate?
My actual stacks

15x0,2
15x0,3
15x0,3
22x0,15
rebound Piston
22x0,1
22x0,1
19x0,1
19x0,1
18x0,1
17x0,1
15x0,1
13x0,1

Basevalve
22 x 0,1
22 x 0,1
22 x 0,1
11 x 0,2
19 x 0,1
17 x 0,1
11 x 0,1
16 x 0,1
15 x 0,1
15 x 0,1
14 x 0,15
13 x 0,15
13 x 0,15

 

[GMP]

Klausen,

Your getting there, but over damped in the comp stack and still running that three stage goofy setup with too much HS. Try a shim shuffle with what you have to make a more progressive 2 stage stack that should be closer:

22 x .1
22 x .1
11 x .1
22 x .1
19 x .1
17 x .1
15 x .1
14 x .1
13 x .15

Now, for that MV you can try and add an 18 x .1 under the 22 x .15 and adjust the float to around 1.4 -1.5 mm with 15mm shims.

I've heard from some guys the piston rings wore fast but mine have been fine for years. If they are bad, try and find a fork with the same dia. piston and use that ring.

Also, make sure your springs are stiff enough and run only a couple mms of preload.

My fork is outstanding, has a firm but not abusive feel and NO deflection.