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I fixed my Showa TC's and now they are horrible. Help!

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Hey guys, so the CR250R I got last year turned out to have a leaking cartridge seal and was probably that way the whole time I had it.  The reason I say that is because I didn't notice any damping changes over 9 months, and the problem is that the forks were absolutely amazing!  Because now that I've replaced the seals and both chambers function corretcly I've been fighting these things and am beginning to hate them.  After riding with 2 functioning chambers they were way too stiff everywhere so I knew I had to do something.  Felt like wooden forks.

So initially I thought I would mimic the damping of basically one leg, since after all, when I went to do an oil change and discovered the leak, the right cartridge was almost empty.  This didn't work and made the fork dive badly and unstable at higher speeds.  It cornered decent on bermed and harder dirt but knifed like crazy in sand.  

So just recently I looked up several enduro/woods stacks and came to a compromise based on a.) I'm mostly riding high-desert single track and some woods, and b.) I weigh 145lbs.  Original owner had it valved for rocky Colorado trails and 180lbs.

so this is what I'm at now, and I have zero feel in the front tire.  First several inches of travel feels almost undamped, highspeed hits are so-so, still too much dive(actually kinda scary to use the brake hard).  Still knifing in sand.  I'm a little confused about the mid's float measurement though.  Trying the feeler gauge method I found about 0.10 or less and based on TT stacks I removed 3 0.10's for approx 0.35-0.40mm.  Most people seemed to like 0.25 but I usually like very soft suspension so I tried a little more.  Based on my stacks, should I tighten it up or look to the base for improvement?  Please help, this bike had near-perfect handling up until I "fixed" them. 

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So here's how I found them when I originally went to change the oil

Original stacks until 3/2017, mid/reb piston was untouched.  Lighter ICS springs, 350cc.  Right side seal leaking badly, comp. assembly almost dry w/450-500cc's in lower.

BASE VALVE

(14) 30 x 0.11 

18 x 0.11(found that OEM didn't have this crossover)

30 x 0.11

30

29

28

27

26

25

24

23

22

21

20

19

Bleed stack disabled

Factory peening on reb/mid shaft

MID VALVE

(6) 20 x 0.1  

(4) 17 x 0.1

Stock float - 0.05-0.10mm (had a hard time measuring this)

REBOUND

(2) 20 x 0.1

18

12

16

15

14

13

12

11 x 0.2

(3) 16 x 0.3

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And here's what I just tried...

Basevalve

went with 12 face shims instead of 14

removed one 30mm after crossover and all odd numbered shims.

MID

removed one 20 and two 17mm shims, supposedly putting float at 0.35-0.40mm.  I'm not convinced by the feeler gauge method, however.  

REBOUND 

left stock. 

 

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What are the spring rates?  (main & ICS springs)

350cc is the average amount for MX, if you don't jump much try the minimum amount and add gradually if you bottom out too often.

 

A 19mm clamp shim on the base valve seems stiff,

16mm (250R) and 14mm (250X) are common in heavier 4 stroke CRF-R TC47 applications.

Edited by mlatour

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0.35 to 0.45 is too much for sand and that base along with softer ics and no bleed stacks , you have taken away everything the fork has to hold it up

I would use your base , std mid and tune from that

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9 hours ago, mlatour said:

What are the spring rates?  (main & ICS springs)

350cc is the average amount for MX, if you don't jump much try the minimum amount and add gradually if you bottom out too often.

 

A 19mm clamp shim on the base valve seems stiff,

16mm (250R) and 14mm (250X) are common in heavier 4 stroke CRF-R TC47 applications.

I'm not sure of either spring rate since the bike was setup before I got it.  I think I checked front sag last year and determined I should go one softer rate, but with a baby on the way I am basically only able to afford the gas and premix to go ride for a while:cry:

I do jump occasionally and here we have deep and sharp whoops so I think the level is good.  I've hit some pretty nasty ones and still don't get harsh bottoming, it's just the initial stroke that is completely vague in feel.  

8 hours ago, mog said:

0.35 to 0.45 is too much for sand and that base along with softer ics and no bleed stacks , you have taken away everything the fork has to hold it up

I would use your base , std mid and tune from that

Sounds like the simplest step to try first, so I'll do that asap.  

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Maybe try returning the float to the 0.25 to 0.30 range, but lightening the midvalve stack.  You might need to sand down the cylindrical collar post, or get a new shorter one.  Or I've heard of using 10mm diameter shims for the bottom of the midvalve stack which are basically inactive.

Edited by heart_of_darkness
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The crossover in the base valve is quite small, making the low speed very soft.  Maybe that's contributing to the brake dive.  And your high speed is very stiff.  Try:

30.1 (x12)

23.1

30.1

28.1

etc. down to

14.1

Start with 325cc oil level, and increase if you're bottoming in the whoops.  If it feels too soft and wallowy on flat areas, you can add 30.1 face shims or increase the crossover diameter.

 

Also, if the shock is still stock (much harder valving), it will make the front feel that much softer.

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I had a spare few hours yesterday so I just ended up returning the mid-valve to stock and leaving everything else as is.  Was hoping to test it today but we got a big storm all day.  I'll report back soon, as I think I might get out tomorrow after work.  

As for the shock, it feels pretty good and I do have it set soft.  My goal is to get the forks as close to how they were as possible then start from there on both ends if needed.

On the last several rides, I was thinking I might try and stiffen things up to see if I could start pushing the speeds in the desert more comfortably, and I got things right I could back the clickers off the other way and have a decent woods setup too.  

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Ok guys, went out yesterday with the mid returned to stock...

that was the key!  All problems fixed, I can actually brake with confidence, minimal dive but the forks still get over small rocks pretty well.  Front end stays up over whoops much easier.  And I didn't even move the clickers from the middle setting.  I think with them backed off I'll probably have an acceptable woods setting too.  

Thanks for the help again.

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