stock shim sequence 93' CR125

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2/2/2017 4:21 PM
Edited Date/Time: 2/5/2017 8:29 AM

Hi,

I disassembled my forks of a 93 CR125 (Showa 43mm) andd messed up the the sequence of the shims.
This doen't concern the valve on the bottom of the fork, but the valve that slides up and down.
The left and right fork seem not to be valved equally either. On one side, the thick washer even is right on top of the valve.

Is it normal that left and right aren't valved equally? And has anyone a picture or desciption of how the shims need to be placed?

Thanks!

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2/2/2017 5:01 PM

Generally speaking it's not normal for them to be different from side to side. Is it the compression side that is different or the rebound side? Also, why did you disassemble the rebound/ mid valve piston?

It would help if you had pictures to see what you have

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2/2/2017 10:47 PM

To put a lowering spacer. Will post a picture today...

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2/5/2017 6:01 AM
Edited Date/Time: 2/5/2017 8:48 AM

First, I took apart the Left fork leg. The rebound valve assembly dropped on the table. I thought 'will sort out when I have the right one as well'.

Then I took apart the right fork leg and the rebound valve fell on the table again! Nothing really mixed up, I only didn't know how to turn the actual valve. Now I've put all parts in a row, I saw that already. However you also clearly see that there's a huge difference between the two assembly's! So the PO must have assembled something wrong. This is really strange, because the fork damper and damper rod didn't show any signs that they have been opened before. One has to drill several small press points before being able to unscrew them.

Please not the compression valve in the corner has nothing to do with the shims pictured here, it still is assembled.

Photo

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2/5/2017 8:29 AM
Edited Date/Time: 2/5/2017 8:54 AM

Unfortunately, the shim stack of the compression valve aren't really assembled well either. They differ. And on the left one, shims are even used as washer, which has bent them. How to get all this sorted..any documentation available of the valves? It's a showa 43mm fork. Shim R1 is 17x1,5 actually, not the stated 17x0,15.

Photo

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2/5/2017 9:11 AM

I have experience with your problem, here is my advice, hope it helps you.

The only people with the actual stock shim stack sequence and shim sizes are people like Race Tech, Pro Circuit ect, but they do not share any of that information, plus it's been over 20 years and that information gets lost in cabinets or boxed and stored when moving.

Next way is to get another matching used unmolested part and disassemble it, if you do not have the stack list then it's always just a guess. Everything matters and that piston has an up and down if you look closely the ports are not the same on the top and bottom.

Last thing is to maybe slowly match the discoloration on the washers with what you think is the right way to assemble the stack, usually that piston and washers have wear marks to see what was lined up where, use a very bright light.

I've been where you are and now slide the stack on to a zip tie and make special marks for UP, been screwed for time making the same mistake.

Good luck with the lowering project.

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2/5/2017 9:21 AM

Thanks for answering. Well, actually all shims have been mounted like this for years, so the wear marks will show the sequence they are in now. I recently got the bike and opened up the suspension to lower it.

I have the shorter spring and spacer. Only remaining step is ordening the shims...

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2/5/2017 12:39 PM

Like Speed said you are likely not going to find someone with '93 specs. Maybe someone over at TT might pop up with it since there is more "tuners" posting there than here. I'm about the only one I know of that posts here, but this isn't actually a suspension tuning forum. Since you're not getting any help over there so far I'll ask you to do a few things first so we can get you on track.

Starting with the first picture of the reb/mid valve, re check and measure #22 to check it's an 11.2 and not two 11.1 stuck together. Check #17 & #18 to verify they're 21.15 & 21.1, hopefully they are both 21.1. Is #7 16.2 or two 16.1 stuck together. Are #5 from the left side and #20 from the right both 6id x 8od collars(can't tell if #20 is a shim or collar) and how tall are they, should be the same height 1.95mm, 2.05mm etc...

Also the rebound pistons should have a bleed port in them, Y/N and if yes what is the diameter if the hole 1mm, 1.5mm etc...

Second picture of the base compression, #9 in the right 18.15? should be 18.1. #2 on right 12.2 or two 12.1 stuck together.

Most of what you need is there with a few missing and a few that don't belong there, but I need those answered to get you close to know what you will need to find.

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2/5/2017 1:19 PM
Edited Date/Time: 2/5/2017 1:25 PM

Rebound/Mid:
No, R#22 is a single shim 11x0,2
Yes, R#17 can indeed be 21x0,1
Yes, R#7 appears to be 2 pcs.16x0,1
Yes, L#5 and R#20 are 6id x 8od collar, both 2,5mm tall
The bleed hole is the one in the picture below? That's 2mm.

Base compression:
Yes, R#9 is 18x0,1 I'm measuring with manual caliper. Would lean more toward 0,1 than 0,15 indeed.
No, R#2 is a single shim 12x0,2

To make things even 'easier' I found another shim of 8,5x0,15mm on the table, during double check. Don't know where it came from.

Would you like me to reorder them and take a new picture?
To get sticking shims apart, I rub them between my fingers or pull with my thumb nail. Any other way to do so?

Thanks slipdog




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2/5/2017 1:50 PM

Double check the left base # 2, 9.15 or 8.5.15 like the one you just found. would make sense that they are the base valve clamp shims.

On your rebound #15 & #16 don't belong, 21.25 is ridiculously stiff for a fork shim. 25yr old technology is a bit weird, but for now pull those two aside. Someone removed all the rebound shims from the left and doubled them up on the right. Coming off the rebound tower each side should have 1ea of.

#7/25 the cup
#6/24 spring
#5/20 collar
#3/21 check plate (22.45/22.5)
*rebound piston
21.1
20.1
19.1
18.1
17.1
16.1
15.1
14.1
12.25 clamp shim

(#8 17.15 doesn't belong in that stack, kind of looks like a blue KYB shim too)

I don't see a picture on your post, but the bleed hole will be in the side of one of the piston ports. If it is 2mm that is kind of big and maybe in '93 they thought that the 21.25 were a good idea to keep the rebound from being too springy with that much bleed. Normally you'll have 21.1 x 4 or 21.1 x 6 instead of one 21.25, but can't be too sure here.

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2/5/2017 2:30 PM

Rebound:
I don't have 2 pcs 12.25 to use as clamp shim. That R#1 and R#2 are 12.25 and 13.25
R#8 looks 'burned blue'. Can take it out. Should I take out L#2, R#22 and R#23 as well? R#23 is 18x2mm.

Base compression:
L#2 really is 9.15 and the one I found 8,5.15
What to do with this shim stack?

Here's the picture:
Photo

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2/5/2017 2:34 PM

You also need a base plate between the clamp (12.25) and the nut. #2 is one, but the closest match looks like #23(20x2). Does #23 have a 6mm id? It's hard to tell from the picture.

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2/5/2017 2:40 PM

Yes, R22/23 don't belong there. ^^See above and R8 should be removed.

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2/5/2017 2:42 PM

In your picture, that is the rebound adjuster bleed, but the rebound piston will almost always have a bleed hole in it also.

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2/5/2017 2:44 PM
Edited Date/Time: 2/5/2017 2:47 PM

Yes Rebound #23 has ID6. But #2 is larger and almost twice as thick.

Don't you mean this with the bleed hole? That's approx 1.4mm. Each rebound valve has 3 such holes. Photo

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2/5/2017 2:55 PM

#23 will have to be your base plate for now, the thickness doesn't matter because it has nothing to do with the shim stack. As long as it gives you enough threads to tighten the nut on it will work. My OCD says to get another #2 but #23 will work in a pinch.

3 bleed ports in the rebound is a lot and that tells me that those 21.25 shims do belong in the stack. One on each side first off the piston before the 21.1s.

I'm heading to a superbowl party right now, I'll help you with the base valve from my phone after I'm there. May be 1-2hrs before I'm back here...

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2/5/2017 2:56 PM
Edited Date/Time: 2/5/2017 2:57 PM

Or do you mean this passage? Can't get into it with the caliper, seems like 2mm or a bit more...

Photo

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2/5/2017 3:03 PM

It's midnight where I live. I still be awake for a while, but if more convenient for you we'll continue tomorrow smile

If better I can make identical base plates on a lathe.

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2/5/2017 4:39 PM

Your base is more difficult because you've missing more, but most is there. #8 on the right base(17.2) doesn't belong there so remove it. #17,18&19 on the left doesn't need to be there and you don't want anything bent anyway. They would just be used as spacers between the cup(16) & the nut(20) if the nut bottoms out on the bottom of the threads before the stack tightens down. You're also missing the 14.1 for the left side between the 13.1 & 15.1 to match #4 on the right side.

The stack from the base plate up to the piston should be something like.

17x1.5 Base plate
9.15
10.1
11.1
12.1
13.1
14.1
15.1
16.1
17.1
18.1
19.1
20.1
21.1
Piston
Check plate(21.5x.4)
Collar
Spring
Cup
Nut

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2/6/2017 9:46 AM

Slipdog thanks a lot!!!. I'll try to get the missing shims and reassemble it. Will post it for later usage by others. Also the shortening. That came out nicely. Thanks once again.

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3/4/2017 11:44 AM
Edited Date/Time: 3/4/2017 11:45 AM

Or might this be the reason that left and right are valved differently? Just finished making them equal. Now start to assembly everything again.

Photo

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3/4/2017 1:49 PM

Oh holy hell, they fluted one of the cartridges... I'm out!

Not really sure what to tell you now other than I'd try to fine a replacement cartridge for the fluted one because standard valving won't work with what was done there.

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3/4/2017 3:32 PM
Edited Date/Time: 3/4/2017 3:57 PM

Mmm, ok, but what does it comprehense technically ? Would better have bought a newer model fork instead of this complete overhaul then. Because it will be hard to find that cartridge as a single part.

Must have been someone smart, one wouldn't destroy the complete valving system without a purpose. Looks like a way to make it progressive..,

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3/4/2017 4:09 PM
Edited Date/Time: 3/4/2017 4:12 PM

That's exactly the intent except usually it was only done back in the damper rod fork days. You'd weld the one big damper hole closed and drill a series of continually smaller holes down the rod to progressively ramp up the damping of the fork. I have seen it done a few times on cartridge forks, but as a whole, speed sensitivity is considered a better way to go than position sensitivity. Kind of the same reason you never see progressively wound fork springs in modern cartridge forks.

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3/4/2017 4:14 PM

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3/4/2017 4:37 PM

Thanks. Althoug I have to watch The European eBay smile Slipdog are you still confident that the shim stack you provided will be fine if I swap the flute with an original one? I bought the missing shims and made that stack

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3/4/2017 4:54 PM

It will be a decent place to start with, but not having any '93 specs to reference it is somewhat of "reasonable guess". For instance the 9.15 clamp shim on the base valve may be a little small and give an overall too soft feel. Maybe using the 10.1 to clamp and leave out the 9.15 would be better or even leave out the 9.15 and 10.1 and use the 11.1 to clamp. Each step larger the last shim(clamp shim) is makes the entire stack a little stiffer.



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3/6/2017 10:28 AM

Damn, it appears to be a mod done by a suspension tuner to make it more adjustable. See image. Unfortunately they didn't have time to look into it at the moment, so let's continue the research sad Interesting though. Photo

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3/6/2017 12:44 PM
Edited Date/Time: 3/6/2017 1:32 PM

Actually this translation is incomplete. In the Dutch version it says:

Compression damping (Right leg, top adjuster)
>affects entire stroke
Turn open when the fork feels harsh at short hard bumps

Compression damping (Right leg, bottom adjuster)
>affects LAST 60mm
-Turn open for short hard holes
-Turn close for longer sand bumps (more damping)

Rebound damping (left leg, top adjuster)
>affects entire stroke
- Turn open for short hard bumps
- Turn close for longer sand bumps

Rebound damping (left leg, bottom adjuster)
> affects start of stroke
- Turn close when the wheel slides away (like a flat tire)
- Turn open when the fork feels harsh at small holes
This adjuster is most affecting the sensitiveness of the fork.

The top adjusters sound logic to me. I only don't understand how each bottom adjuster can have a different effect. The adjusters only adjust the bypass flow, isn't it?




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3/7/2017 5:25 AM

Looking it over and having now seen that you have the fluted cartridge, the original settings make a bit more sense. This is actually a lot like the current Cobra 50/65 CARD forks in they also have one standard cartridge side and one fluted cartridge. The only difference is their fluted cartridge has no base valve so the top is considered the "bottom out adjuster". It uses a extremely stiff compression stack on the mid valve side and the adjusters bleed will have no real effect until the piston passes all the other bleed holes in the cartridge. The fork would almost hydraulic lock after the piston passes the last cartridge hole since there's no base valve and that's why the top adjuster bleed has so much influence over the final part of the stroke.

This design still retains a standard base valve and the mid compression is just a check plate giving very little damping unlike the Cobra's almost solid mid so I would assume that's why they consider the base valve on the fluted side as the bottoming control adjuster(last 60mm). That would seem to me to be much less effective than the CARD design since it will bleed so much pressure off through the check plate mid and base valve stack, but I have no experience with this Reiger system.

I would also agree that the base valve should have no effect on rebound adjustment since they work on a check plate refill system. The adjusters bleed will only be effective when there's resistance through the piston via a valving stack so the adjuster can bleed off pressure. With a check plate there is no pressure to bleed off.

Obviously your best bet at this stage it to consult Reiger on the system you have since all my earlier advice with the valving was before I knew the one side was re engineered.

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