Marzocchi setup help - 08' EC250

[ferguscawley]

Where can I buy shims in the uk?

I got them from windwave in the UK - they are the marzocchi importer. Speak to Dan there. He is very helpful.

http://www.marzocchi.co.uk/

You need to remove the compression stack from your forks - on the sachs this is simple as you can just turn the fork upside down, remove the entire compression valve assembly by rattling it out with a 19mm socket. Then its simply a case of removing the nut from the top of the assembly, removing the small spring and piston and then the shims are available toyou.


Its been over 2 years since I did a marzocchi fork so cannot remember exactly how I did it. I thionk you have to split the forks for the marzocchi but am not certain.

Fergus

 

[nick790]

Ok, I have my forks apart and there are signs that they have been apart before, I checked for any spring markings but found nothing. Is this normal how do I know what springs are fitted???

I also had a quick look at the comp valve, they dont seem to have a bleed shim as described in other threds, but I will post up the stack sizes and some photo's soon for your comments.

I realy like to know what springs I have fitted

 

[iancp5]

I realy like to know what springs I have fitted

Unfortunately if they're not marked there is no way to be sure without having them measured by a suspension specialist. Theoretically if you have some weights and can keep one from bending you could put the weight on and see how much it compresses.

Standard is 0.42 (I think that's Kg/mm but could be N/m or something)

So ... stick a 10Kg weight on and see how much one compresses.

Alternately pump someone else's forks and see if they feel the same but this is tricky as they could have different air gap, different oil and clicker settings.

 

[nick790]

Had the forks apart tonight, found the following.

In the comp valve I have 17 shims

1, 22x10
2, 22x10
3, 22x10
4, 22x10
5, 22x10
6, 22x10
7, 11x20
8, 21x10
9, 20x10
10, 19x10
11, 18x10
12, 17x10
13, 16x10
14, 15x10
15, 14x10
16, 13x10
17, 12x10

Your notice no bleed shim against the piston, but I did find this half way dow the stack

Looks like at some point it was against the piston as a bleed shim??

So does anyone think someone hase been messing, or is this ok?

Also, 1 litre is'nt enough oil

 

[nick790]

Come on, someone must have some thoughts??

Also, how do you get the rebound valve out?? could see it in the tube but was'nt sure how to remove it, I'de like to have that apart at some piont ane see whats in there.

Is there anywhere I can go to fine out the standard shim stacks??

Once I have refilled the forks with oil, can I then turn them upside down and buzz the comp valve out, make adjustments, and refit without disturbing the oil??? or will this cause problems?

 

[nick790]

One at a time gents!!!

 

[nick790]

I had them apart again tonight,

Checked the rebound stack:-
1,22x1.0
2,12x1.0
3,19x1.0
4,17x1.0
5,15x1.0
6,12x1.0


After the mass of replys you guys have given me and the fact that I have a race on sunday I have decided on changing to the following:-

Rebound-

1, 22x1.0
2, 21x1.0
3, 19x1.0
4, 19x1.0
5, 18x1.0
6, 17x1.0
7, 15x1.0

This is as close as I could get to Pobit's stack with the shims I had available.

Compression-

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

Dont ask me how I ended up with this, I looked at alot of posts, and got some info from Marzocchi UK and had to make do with what shims I had.
I guess sunday will be the telling of it, to be honest I dont think it could be worse. The rebound has far more control than it did before, I can tell that by pressing against the ground.

I write this for my own notes, as nobody seems to have any veiw on the subject?

 

[MattR]

I have not did my own fork revalving yet, but can offer a few suggestions based on my suspension background (automotive shocks). The shim/disc stack is very sensitive to both diameter and thickness changes. The stiffness of a disc is proportional to the cube of its thickness (in other words... thickness ^ 3). The real equation is complex but this will give you an idea. So changing even a single disc can have a dramatic effect on the entire valve stack. Also, a small diameter disc directly below a larger diameter diameter disc acts as a "pivot" disc. It causes the larger disc to pivot/bend at that location.

Just looking at the numbers you posted... your original compression stack looks very stiff. It's no surprise that you had harshness over small stuff. You had 6 discs with same diameter and thickness for the initial stage. Very stiff! Your newer compression stack should be better, but only riding it will tell you. The 14mm diameter disc will be the first pivot disc and breaks the stack into 2 stages. The discs listed below this one look like a pyramid stack and will contribute to the mid to high speed stuff.

Your rebound stack now looks quite stiff with no smaller diameter pivot disc. You basically have a pyramid stack (think upsidedown decreasing diameters).

Leave it alone for now and ride it... let us know the outcome and make only a few changes next time. A word of caution: it's best to make 1 or 2 changes at a time and test the result. You made a whole bunch of changes and are really starting from scratch here. Good luck!

 

[getndirty]

Ok, so these are my idears so far, please advise as you see fit.

1, increes oil air gap, I'll go quite low at first and top it up to get the right feel.
2, replace fork oil, the bikes about 16 months old. The manual says SWA 5-7.5? what should I use?
3, Check lower fork clamp bolts, how tight? any thred lock?

Now we get to the trickier part, after reading through some threds, i was thinking of making some shim stack adjustment, can anyone advise me on exactly what I should and should not touch? I unterstand the the forks may not have enough rebound adjustment? and I read you can remove a bleed shim to speed this up? Can anyone advise?

Should I look at the comp stack at all?

Thank for the help, just like to add the only time I've ever been inside the fork are for standard sevice resons, this is why I'm keen to get as much info as possible, not that I'm worried about doing the work, infact I find the whole subject quite intresting .

I'm zero help in the re-valving department, but I just re-sprung my zokes last week with springs that I got from Les at LTR. I'm 225 dry and 250 in full gear. He recommended I run 120mm oil height and said the zokes like 7.5w high quality oil. Re: lower fork clamps - tighten the middle screw to 10 Ft Lbs and snug the other two up. He didn't mention threadlock - I've checked the torque on both clamps twice (two rides) and haven't seen any movement yet.

Hope that helps a little.

 

[nick790]

I have not did my own fork revalving yet, but can offer a few suggestions based on my suspension background (automotive shocks). The shim/disc stack is very sensitive to both diameter and thickness changes. The stiffness of a disc is proportional to the cube of its thickness (in other words... thickness ^ 3). The real equation is complex but this will give you an idea. So changing even a single disc can have a dramatic effect on the entire valve stack. Also, a small diameter disc directly below a larger diameter diameter disc acts as a "pivot" disc. It causes the larger disc to pivot/bend at that location.

Just looking at the numbers you posted... your original compression stack looks very stiff. It's no surprise that you had harshness over small stuff. You had 6 discs with same diameter and thickness for the initial stage. Very stiff! Your newer compression stack should be better, but only riding it will tell you. The 14mm diameter disc will be the first pivot disc and breaks the stack into 2 stages. The discs listed below this one look like a pyramid stack and will contribute to the mid to high speed stuff.

Your rebound stack now looks quite stiff with no smaller diameter pivot disc. You basically have a pyramid stack (think upsidedown decreasing diameters).

Leave it alone for now and ride it... let us know the outcome and make only a few changes next time. A word of caution: it's best to make 1 or 2 changes at a time and test the result. You made a whole bunch of changes and are really starting from scratch here. Good luck!

Sorry about that, I was getting desperate. Thanks for the help with this.
I've tried not to anything to drastic, but as you can see, it looked like some big changes needed to be made.

I'm gonna run it tomorrow and see how it goes, unless i'm plesently suprised, i'll probably get it professionaly re-valved. I really wanted to make some changes so it was more bairable for tomorrow.

We will see

 

[moto9]

I am currently testing some different valve configs.
I didn't remove any face shims because I want it to ride higher in the stroke, so I moved a couple of shims in the HS portion of the stack and flipped the pistons...not sure if ther were upside down.
I also added some float to the mid valve and stiffened up the rebound a tad.
I eventually will opt for stiffer springs (46's)
I will see how it works tomorrow.

 

[nick790]

Raced today, and I can say that I have made some progress. Less harsh feel all over, front sit up nice over small woops, rocks and roots not a problem.
I still have about 2 inches on travel on the fork un-used and I would now describe it as firm. Also, how much for sag should I have? I seem to have alot, not sure how much though.

I managed to have a chat with some other gasgas riders in the padock today, one guy (very fast) who is alot heavier than me said he has gone up a size on his front springs, when I felt his bike it seemed way softer than mine.

So now i'm thinking I have the wrong springs, so I'm going to see if I can get some standard ones for it. I set the oil hight at 120mm if I changed this would I get more travel or a higher ride hight?

I had the compression at 20out, so should I go softer with my comp valve?

 

[nick790]

Can anyone tell me if the EC200 standard springs are the same as a 250?

Many thanks.

 

[MattR]

Can anyone tell me if the EC200 standard springs are the same as a 250?

I believe the EC125/200 has 4.0 spring rate, EC250/300 has 4.2 spring rate, and MC250 has 4.5 spring rate.

 

[MattR]

I still have about 2 inches on travel on the fork un-used and I would now describe it as firm. Also, how much for sag should I have? I seem to have alot, not sure how much though.

I like to have my forks use as much travel as possible and bottom out on hard hits only. I would soften the compression a bit more. It may be as easy a removing one of the 22mm discs. Since you are 20 clicks out, you are at the end of your adjustment (fully out). I would make a slight tweak to the valve stack to soften the damping and set the clicker to 14-16 out.

I set the oil hight at 120mm if I changed this would I get more travel or a higher ride hight?

At 120mm, you will have more air space versus the standard 110mm. More air space is softer. If it is too much, you can bottom out too often... but it doesn't sound like an issue yet.

 

[GMP]

With the shims you have, move the 20mm on the other side of the 14mm pivot. Rebound looks OK and should be an improvement over stock. 120mm oil is a lot higher than I run for rocky woods, likely why your not using all the travel. Try 140mm. Avoid going to high oil levels and excessive spring preload, go to stiffer springs instead if its too soft. Keep the fork spring preload to about 8mm max, I run about 4 -6mm.

FWIW, I would love to help you and post some specs, but I feel it is unethical to post such specs as they were provided to me by a proffesional tuner (LTR) who happens to be a sponser of this site, as well as a friend who has gone out of his way to help me and others here over the years. What I will do is steer you in the right direction however with more general information. Anythig else I have experimented with myself I have no problem with, and I encourage the sharing of this information as thats what this site is all about. I think everyone can be happy with that.

 

[nick790]

Thanks guys, I feel like I'm making some progress now.
I've bought some second hand springs from a EC200, I was told there the same as the 250? Anyway there were cheep so no great loss if there no good.

I think I'm going to remove one of the 22x.10 shims in my compression stack, by my understanding this will give me less low speed damping? This would improve the comfort of the bike and make it a bit less firm??

I will also try dropping the oil light to 140mm to try and get the full stroke of the fork, I can always top up as needed throught the air bleed screw.

GMP - I understand that you dont want to "give to much away" as LTR obviously need to make money from there expeirence with suspension, but being in the UK I am never going to send my suspension to them, it's just not viable. Unfortunatly the demand in the UK for "Gasgas suspension experts" is not great, so finding someone with expeirence with Gasgas and Marzocchi are limited. Sure there are plenty of suspension tuners that will give you improvements, but non that will sell you what you need. Maybe if you see something I am doing wrong or obvious improvments I could make, maybe you could PM me, so not to put it on the public forum? It would be a great help.

Anyway, thanks again fella's

 

[nick790]

And another thing, spring pre load, I'm guessing this is controled by the spacer in the fork? This is not adjustable on my fork unless I trim or add to the spacer, I'd say the one in there is about 70mm from memory. I also do not know much preload is in the sping whenit's installed.

I'd like to know how much rider sag the forks should have? or what is normal?

 

[MattR]

My bike and rider sag settings are listed here:
http://www.gasgasrider.org/forum/showthread.php?t=4478

Regarding the 22mm valve disc...
Removing this disc will allow the valve stack to deflect easier at lower speeds. After the first stack deflects, it will deflect until making contact with the second stack (below the 14mm pivot disc). As the stack blows off easier, it may engage quicker into the second stack which may result in good or bad mid speed characteristics... only you will be able to say if you like it or not. Damping characteristics are very subjective!

Glenn's suggestion is also one to consider...
If you reposition the 20mm disc to below the 14mm pivot, then you will also get a similar first stack. However, you will be adding a disc to the second stack (more mid to high speed damping).

In either case, you should make a change to get the compression clickers more to their middle position. Once you get the valve stack in the ball park, the clickers are very effective for trail-to-trail modifications. I can feel when the clickers are off by a few clicks.

 

[MattR]

Another variable to consider is fork oil viscosity. Without anymore valve changes, you could try out good quality 5wt fork oil (such as Spectro). This will effect both compression and rebound damping. Since your compression clickers are almost fully out, you could turn them in for the lighter 5wt fork oil. This thread is getting long, so I don't recall what your rebound was set at. You may need to add more rebound damping to also compensate for the lighter oil.

Just a thought since swapping oil is pretty quick versus disassembly of the entire fork.