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Showa TC for Woods on a CRF250X

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I ride single track trails with a lot of trail debris and found the stock damping way too stiff, but not so bad with the clickers at zero but then the bike wallows a lot.    Trail debris ranges from lose rocks the size and shape of bricks to cinder block sizes, plus embeded rocks; sometimes a few, sometimes a garden.

I did replace the .46 spring with stock .42 and that helped. I pulled two face shims and added a 23 xover shim at the end of the 30 x 14 face shims, only very slight improvement.

170lbs wo gear, old use to be B level Enduro rider.

Rock Oil SVI 5.

 

Current BV stack

30x14
23     xover
29
28
27
26
25
24
22
21
20
19
18

 

I would appreciate any suggestions

 

On edit:  added original stack which I think is OEM for 2005 because while no obvious sign of peening the nuts had a lot of bind at the last few threads on the shaft and I needed to dress the shaft ends with a small file. 

 

BV (all .10mm shims unless otherwise noted)
30x16
29
28
27
26
25
24
23
22
21
20
19
18

 

MV compression
19.9 x6
16.8 x4 (total stack thickness is 0.99mm)
2.12mm long dowel (fits in valve body recess)
.2mm float
9.8 x 3 (.20mm)  inactive shims w 5.8mmID

 

MV rebound:
19.9 x2
17.8
11.8
14.8
13.8
12.8
11.8
10.8 (.20mm)
15.9 x3
plate

Edited by Chuck.

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I would remove 4 face shims

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without knowing the midvalve any advice is useless....

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30x16
20    xover
30
28
26
24
22
20
18

16

midvalve 20.10x4 and 17.10 x 4 with float 0.20

reb

20.10x2

12.10

18.10

16.10

14.10

12.20

thats my suggestion for trial woods

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If you are not going to be doing any decent size jumps you can pull 4 to 6 face shims out of the bleed stack. This helped both my bikes forks greatly from deflecting off of rocks roots or other sharp edge objects. I also run 400 ml of oil to prevent bottoming out.

The Dogger has a great thread on diy suspension tuning that is pinned in the CRF450R forum.

Edited by cleaner1

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Thanks for the Dogger link.

 

So far suggestions seem to favor reducing the number of face shims in the BV and MV, using a smaller pivot shim, and pulling every other shim from the tapered stack. 

 

without knowing the midvalve any advice is useless....

 

Sorry for the delay it has been a long weekend.

Here is what I found in the MV along with the previously posted BV, I think this may be stock valving.

 

BV
30 x16
29
28
27
26
25
24
23
22
21
20
19
18

 

MV compression
19.9 x6
16.8 x4 (total stack thickness 0.99mm)
2.12 long dowel for 1.13mm float
9.8x.2  x3    shims

 

MV rebound:
19.9 x2
17.8
11.8
14.8
13.8
12.8
11.8
10.8x.2

15.9 x3
plate

Edited by Chuck.

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Mv stack looks stiff! ! But

Is that right ? 1.13mm float ? Never heard of a showa with more than 0.7

Edited by mog

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Good catch! I missed the recess in the valve body that the collar fits into.

 

The collar sits proud of the valve body and my meaurements with calipers were inconsistant so I assembled the shim stack onto the body with the collar.  And then used some other shims to check how proud the collar was from the stack when all held together with finger pressure. An added .1mm shim was not proud of the collar, a .2mm shim was slightly proud so I then used feeler stock and found the dowel to be proud between 0.008 and 0.009". That converts to .21mm, not much float?

Edited by Chuck.

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huh? That is nowhere close to stock. It looks horribly stiff for trails. I think you are quoting an R setup.

 

From what you posted an X has a 14 clamp and less face shims on the base, 3 less 20's in the mid with .2-.25 float.

 

Stock springs are .42 with a lot of preload, just add the R springs to fix the preload issue. 

 

Try that for starting.

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That's super stiff valving as Chris said

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OEM CRF R vavling

 

Could try

 

30 .10 x12

23

28

26

24

22

20

18

16

14

12 .30

 

4-6 16's of the bleed

 

20 .10 (3)

17 .10 (3)

@.25 float

 

350cc drilled and ported spring seats

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This thread sure is getting confusing. What bike are we talking about here?

 

05 CRF250X used for technical single track with lots of rock debris and tree roots.

The bike had a 19" R rear wheel on it when I bought it, and now it seems to also have R valving in the forks. I hope the PO who made the fork changes was too lazy to do the shock. :rolleyes:

Edited by Chuck.

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OEM CRF R vavling

Could try

30 .10 x12

23

28

26

24

22

20

18

16

14

12 .30

4-6 16's of the bleed

20 .10 (3)

17 .10 (3)

@.25 float

350cc drilled and ported spring seats

I would think this stack would soften up your forks significantly.

I run a very similar stack on both of my Hondas. I have found that taking out 4-6 face shims off of the bleed stack makes a huge difference on the forks deflecting off of the roots and rocks. I run 400 ml of oil to keep from bottoming out, run 1.6 IC springs to plush up the ride, and run a more tapered MV stack with less float. Really like the way my forks feel and handle.

I weigh 225 with gear, 48 years young, and am a mid B pack rider.

My $.02 for what it's worth.

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I'm going to show my lack of knowlwdge regarding suspension terminology; what is "4-6 16's of the bleed"?

 

I'm also shim challenged, so lacking someone selling me some shims or pointing me to a supplier, the following is an idea based on rearranging/pulling existing shims, Suggestions appreciated.

 

BV

30 x10
23 xover
28
26
24
22
20
18
16  f/ MV reb or one of the 9.8x.2 from the MV comp.
19
21
25
27
29

 

MV comp
19.9 x3
16.8 x4

.2 float
9.8x.20 x3

 

MV reb

19.9 x2
12.8
17.8
14.8
13.8
11.8
10.8x.20
15.9 x2
plate

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I always thought the stock 250x stack worked pretty good for that kind of riding so you could just put it back to stock and try that.

 

shim links:

 

http://www.racingsuspensionproducts.com/shim/shim.html

 

http://www.csrsuspension.com/home/shims/

 

http://www.mx-tech.com/

 

http://www.suspensiondirect.com/parent_category/1500/5-Shim-Parts/1.html

Incomplete without telling us where stock  stack info can be found. I looked/asked forever  for stock stack settings for my CR and never found them. All I ever got was "I think" or "if I remember correctly" or,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

Edited by YHGEORGE

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Stock for crf250x of that gen would be:

 

30.1 x14

27.1

29.1 x2

28.1 x2

27.1

26.1

25.1

24.1

23.1

22.1

21.1

18.1

16.1

14.2 x4

 

20.1 x3

17.1 x4

10.2 x3

1.95mm collar

.45ish float

 

20.1

19.1

18.1

12.1

16.1

14.1

13.1

12.1

11.2

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I always thought the stock 250x stack worked pretty good for that kind of riding so you could just put it back to stock and try that.

 

Thanks for the links, I had done web searches for shims but didn't come up with all of those sources.

 

The bike is a X but it seems a PO put in R valving and I don't know the stock X valving to convert back, I did however install stock springs.

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Look up for X valving.  It's far more likely for someone to swap in R forks than would it would be for someone to change the valving to match R specs. 

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