DIY revalve of TC forks?

I have the TC 50mm forks that came stock on my 09 WR150. I have already bled the air out and they were not too hard to work on. I looked at the manual and it seems like I would not have to go much further or have any special tools to get to the compression and rebound shims.

Has anyone been into them and if so is it hard to do yourself? I have no idea how to modify the suspension with shim changes but it I took them apart and posted what is in them would someone here be able to make some recomendations? I hope I can work with what is there but I guess I should be prepared to order shims if needed.

Are these the Marzocchi dual chamber forks? I have a 08 TXC250 with these forks ... Supposedly, the TC and TXC bikes of the 08 era had the same forks with different valving ...

I've had made apart for oil changes and looking at the valves and yep, easy work, no special tools ... I lowered the oil volume in the outer chamber to remove some the harshness on the trails ... Becareful with the shims ...they will be stuck together with just oil and will just fall apart in your hands when removed ...

What are you looking to do? I can take mine apart again and get the stack from a standard TXC configuration if you are wanting to get a softer trail type setting ...

I like my bike on the trails but wish I had something a little stiffer for the tracks for jumping ... I'd be interested in your TC stack maybe I can try to duplicate it here ...

Mate have a look at the free educational video on Rocky moutain atvmm site for both dual cartridge (TC) and open cartridge (TE) forks. They are really so helpful.

If you post your stacks I can help you make changes. You may not even need to buy any shims, it just depends on what in there and how you want to make it work.

NWrider...I hope you are OK with me showing my stacks here also ... I hope we can learn from all this ...

1) On ST \ woods riding, these forks were a little harsh and deflected off sharp edges at lower speeds ... I corrected this by lowering (-20ML) the oil volume in the outer chambers and adding pre-load (via the inner clip) to carry the forks higher in stroke ... Seems good here till I get the speed up ~3rd gear or so and some of the harness comes back ... If something can be done with this higher speed harshness, that would be a plus...

2) On tracks on jumps, I nearly bottom the forks on jumps that are not very long but have kicked me in the air ... I corrected by adding oil (+10ML)to the outer tubes.. this helps the bottoming but makes the forks really hard in about all other cases ... If I had a setup for jumping that helped on the tracks and did not make the forks too harsh else where on the tracks, that would be great ... something more like a TC stack would work I think ...

Thanks for any suggestions ..

Rebound stack from 08 TXC250; here are the shim diameters, reading from the top of the piston, at the small nut, downward on the shift.
15mm (1) , 17mm (2) , 11mm (3) , 23mm (4) , 23mm (5) , The valve , 22mm (6) , 19mm (7) , 22mm (8)


Here is the compression stack from 08 TXC250. You can see the red cap to the far right indicating the top of the fork ...

UPDATE: One of the 22mm shims is thicker than the other 2. Not sure which one as I did not notice this at tear down time nor did I have a device for measuring that small a thickness but one is thicker 4 sure ...

Compression shim diameters, in MMs reading from left to right on the pic;

12mm (1) , 22mm (2) , 22mm (3) , 16mm (4) , 12mm (5) , 22mm (6) , 21mm (7) , 19mm (8) , 17mm (9) , 15mm (10) , 13mm (11)

Can you measure the diameter and thickness of each shim in MM ?

The far left shim is a bleed shim, it may have a lot to do with most of your issues. The simplest thing for you to do would be drop the bleed shim and see what you think.

I added the diameters of the shims above in MMs ...that is all I can read on the tinker-toy device I have for measuring ... I can't measure the thickness as they are too thin for this device I have ....

Rebound numbers are updated but no pic... Any suggestions here before I put them back together with the bleed shim off the compression valve removed? I'll go back to ~260 ML of oil in the outer chambers as before and see how it feels on the trails...

What about bottoming resistance for the tracks? I'm interested in seeing what that TC stack looks like as compared to the TXCs....

NWr, no problems with the tear down so far but the PDF from Marzocchi says to wrap the threads on the inner chamber rod when you pull it out of the inner chamber for accessing the rebound valve, it feels like a seal is there that the rod must pass through so the tape is used there to save this seal ... Also, unlike the compression valves, the rebound valves has multiple shims on both sides of it ....

I just found a problem with the second compression stack when I was going to remove the bleed shim ... It differs in 2 ways from the compression stack above ...

Differences 1n stacks:

1st difference: Additional 11mm shim in stack as the last shim on the cap side (right side of pic above)
2nd difference: The bleed shim on the far left in the pic above, is in-between the two 22mm shown above to the far left ...

I'm guessing to remove the additional 11mm shim because it is the only 11mm I have and I can't duplicate the stack on the other side ... Not sure what to do with the other shim that was miss placed (or the first stack was incorrect) unless just remove it...

Rebound stacks were identical as expected ..

Update: 11mm shim was not missing ... user error

So much for Q.C., huh?

OK, try this, remove the odd 11mm shim and set it aside. Take the 12mm shims from the top and replace the bottom 13mm with them. Take the 13mm and add it to the MidValve under the 19mm.

Your main stack will be like this:
22mm (2) , 22mm (3) , 16mm (4) , 12mm (5) , 22mm (6) , 21mm (7) , 19mm (8) , 17mm (9) , 15mm (10) , 12 in place of 13mm (11)

Your MV will be like this:
The valve , 22mm (6) , 19mm (7) , 13mm from base, 22mm (8)

OK ... I found the scoop on the MV and rebound and such ....

What should I expect from these changes when ride tomorrow?

Whoops! I found the lost 11mm on the valve ... Do I still leave these off or add them to the bottom of the stack?

Replace the 13mm at the bottom of the MV stack with the 11mm for now.

What to expect? I'd rather just set this as a base line and go from here. You report back what you think of it and we'll see if you need to adjust from there. I don't want to influence what you think by suggesting what you should feel.

Ok and thanks ... I feel like I should run the outer chamber oil about ~10ML lower (270ML) than the 280ML mark as a starter as it is easier to add some oil than remove it for me ...

I usually ride a couple days at least before I make up my mind on any changes unless there is something that has changed significantly in one way or the way on the feel of the ride...

The next few days should be on the trails but I should be able to do at least few laps on a track to test it there also ...

No problem. Just give that a work out and see what you think and we'll go from there. Just record everything you've done or do so we can adjust off that base.

Also, don't be afraid to move the clickers around. Start with the recommended settings. The rebound should need a lot of change, but I recommend that you move the compression around a lot.

You may find that trying to do trail and moto with the same stacks a bit of a compromise. Use the clickers to see if you can compensate. Fully open and fully closed are testing options.

Maybe ray_ray will have this all figured out before I get around to pulling my forks apart. I am not sure I need to mess with the rebound. If someone has some good stacks to use I might go for it but I am not sure what I would change. For the compression it is just too firm. It would be nice if the little stuff could be soaked up better.

Normally you don't need to do anything with the rebound, the clickers will usely get it. What I suggested was a mid valve mod.

The two shim moves were to address his complants about the stock setting. Removing the bleed should help it stay up in the stroke, then we softened the compression stack overall since we took out the bleed. Then softened and increased the point of contact distance on the mid valve to lessen the spike on the faster stuff.

On the jumps that kick him in the air this may not be much help. Less bleed and less clicker opening might help, but he just needs to learn to "Bubba scrub" or something over stuff like that.

I have to say this was a very good improvement ... I got to ride on a few trails, some fast woods roads with many large rocks & ruts & pot holes & washes across the road, of all sizes and even a few jumps on a track ... It will take me a while to absorb all the changes here that have come forth .... ESP on the jumping ...

First the clickers were set at the default settings for both the rebound and CMP (15 clicks out from closed) .. this felt OK but a little firm...not harsh, no big hits felt thu the bars, just a firm stroke on the forks ... I opened the CMP up another 5 clicks, felt better, opened the rebound 5 clicks ... Felt better with some limited trail riding as a test ...

Then right before hitting the trails for some real testing, I went and did a few small jumps ... Felt good but I thought the forks were using about 90% of the travel and this was about where I was at before the stack change ... So I closed the CMP clickers up 10 clicks ... This put me ~5 clicks less than the default CMP settings ... This reduced the about of fork travel used on landings and felt better to me, ESP on the landings ... I closed the CMP 5 more clicks ... This started to actually change the way the bike acted on the face of the jump (and in the air) as the forks did not compress so much, so the rebound leaving the face was less ( I guess ... still not a real jumper guy) ... I was really digging all these changes ... Felt much better landing also as the bike felt cushioned (and stood up) when it landed and not just soft ...

Then on to the trails and I opened the CMP values up all the way and then added 1 click back in ... I would use the terms soft\firm and smooth for the overall action on the trails and fast woods roads ... I never hit anything that really felt hard or gave me a big bar bang except some very big sharp objects when traveling at high speed(~30mph). This was an improvement 4 sure... Zero deflection, zero head shake ....

This small stack change , as compared to running the lower volume oil, is quite a bit better as it seems to bring the clickers back into the picture. I never got very much positive action from the clickers and bottoming resistant was greatly comprised with the low oil volume ... Low oil volume did remove the harness I was feeling from forks but had the mentioned side effects...

I'd say to NWr, make these changes ... thank you for starting the thread, thanks MH for the changes, and testing has not conclude yet ...continued 2morrow ...

Good to hear. Glad you liked it.

Two more questions for the future as I have no plans to make any more changes other than clickers for now:

1) What stack changes will make the forks stiff for tracks?

2) What stack changes will make the ride softer for the trails?

If you un-did the MV and base shim changes it would become much more Moto.

How much softer you want it and do you mean just overall or in the first 1/3 of the stroke? Do you still have the preload set higher?

The original stack had limited bottoming resistance and the overall stroke was a ~little soft for tracks ... It would work on the small tracks here but any mistake on a small jump and the forks would bottom or be at 98% ...

I was hoping the OP would post that TC stack for comparison

The changes you gave so far might be OK for the track, I just have not fully tested there yet ... I was just asking if there was another simple change to help to stiffen the bottoming resistance even more ...

If I went softer, I'd like the entire stroke or the top 1/2 or more to be softer for trails only riding ...

Yep, I have the preload set high ... I was gonna remove some preload with the current valving and see how that felt before I changed the stack any more ...

As I said, I test slowly over a days ride or more ... but will be changing the preload later this week I hope ... It is the rainy season here and rains almost every day at least once and the tracks are a little muddy