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DDT Kyb TC fork going from Wr450 to Yz250f

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Used my DDT tc fork from an yz250f-06 on my wr450f -07 and it worked relly good (i loved it) in the rocky woods riding i do, then i bought a yz250f-08 and mounted the forks on it with new 0,42 springs (used 0,44 on the wr).

The fork was not working at all!! Should i lessen the preload on the 62 and 175 springs on the midvalve when going to a so much lighter bike?

Wasn`t able to use ful stroke on the 250f even with 0,42 spring where the 450f was using full stroke with 0,44s.

Any suggestion would be really good since i got a big race in the weekend

thanks Henric

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Took the fork apart and i didn`t have any preload at all on the 2 small springs.

Funny that it worked so well on my wr450 -07

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Having a epnp kit laying on my workbench and wounder if that would help me getting the fork better for the 250f?

If i could get the same feeling that i had with it on the 450 it would be awsome.

Dave do you have any comments on what to do ??

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henrics,

what weight are you? and which enpn kit do you have? the 1.0 or the 1.4

which kit do you have, theres a revision on the coller legnth, if you have the 7.3 collar you need no preload.

also what oil volume did you run?

mark.

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Well i weigh ~95kg

I have/use 13N ics single spring right now( it came with the first sdt kit i bought) and the small springs laying on my bench(i have never tried them in the fork). Maybe the 13N are not suitable to use as primary springs?

I have also the 7,3 collar.

I have 310ml 5w oil in outer camber (5w oil in inner camber).

The funny/sad thing is that it worked so well on my wr450f -07 and dont on my 08 yz250f. currently running stock -08 fork with 4 faceshims less and smaller clampshim and like it better than the ddt tc fork..

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Used my DDT tc fork from an yz250f-06 on my wr450f -07 and it worked relly good (i loved it) in the rocky woods riding i do, then i bought a yz250f-08 and mounted the forks on it with new 0,42 springs (used 0,44 on the wr).

The fork was not working at all!! Should i lessen the preload on the 62 and 175 springs on the midvalve when going to a so much lighter bike?

Wasn`t able to use ful stroke on the 250f even with 0,42 spring where the 450f was using full stroke with 0,44s.

Any suggestion would be really good since i got a big race in the weekend

thanks Henric

What do you mean by “not working at all”?

What problems did you have?

Something seems a little weird here.

Took the fork apart and i didn`t have any preload at all on the 2 small springs.

Funny that it worked so well on my wr450 -07

Okay…now it just got a little more weird.

Are you saying that the 175 and 62 springs are loose on the stem?

Let me know precisely what’s happening and we’ll be able to figure this out.

:worthy:

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Thanks for answering Dave.

I`m sorry they are not loose on the steem but there are not any extras

16x0,30x12 and 8x0,25x11 to preload them further.

It is deflecting alot on rock and ruts and i cant trust the fork as i could on the 450. Having ~2" travel left where i used full travel with the 450.

Tried 4,2N forksprings (used stock yz250f -06 on the 450 0,44kg i think)

I know that the wr450 is alot heavier than the yz250f but im around 210lb and dont think i should have to use softer springs ?

This is how its setup now.

13N ics spring( not tried epnp yet)

Base

2x32.11

18.11

12x32.11

30.11

28.11

26.11

24.11

22.11

20.11

18.11

16.11

11.1,43

20.1,60

11.25

11.25

reb

4x20.11

13.11

20.11

18.11

16.11

14.11

4x13.15 (instead of 2x13.30)

14.30

m6x1.0

mid

20.11

20.11

16.11

20.11

18.11

14.11

11.25

11.25

17.30

spi 175 spring

spi 62 spring

7.25 spacer

post

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Henric ! don't use the 13 N singel spring togheter with the small EPNP spring, it's to long and would go blind, you have to use the 10 or 14 N spring,

You have a wery small gap for the fork bleed on the base, maby you have to change those 2 x 11 x 0,25 to 11 x 1,43.

I think the problem is in the midvalve, try change to a little softer valving.

20.11

16.11

20.11

20.11

18.11

11.30

11.30

17.30

Rob

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Thanks for answering Dave.

I`m sorry they are not loose on the steem but there are not any extras

16x0,30x12 and 8x0,25x11 to preload them further.

It is deflecting alot on rock and ruts and i cant trust the fork as i could on the 450. Having ~2" travel left where i used full travel with the 450.

Tried 4,2N forksprings (used stock yz250f -06 on the 450 0,44kg i think)

I know that the wr450 is alot heavier than the yz250f but im around 210lb and dont think i should have to use softer springs ?

This is how its setup now.

13N ics spring( not tried epnp yet)

Base

2x32.11

18.11

12x32.11

30.11

28.11

26.11

24.11

22.11

20.11

18.11

16.11

11.1,43

20.1,60

11.25

11.25

reb

4x20.11

13.11

20.11

18.11

16.11

14.11

4x13.15 (instead of 2x13.30)

14.30

m6x1.0

mid

20.11

20.11

16.11

20.11

18.11

14.11

11.25

11.25

17.30

spi 175 spring

spi 62 spring

7.25 spacer

post

Personally I see a few issues here.

1) at 210 LB your spring rates is off

2) your reb setting is way too stiff

3) go to the EPNP 10nm

4) suggest changing the Co position further down the stack on the base.( combinaton of all the above is allowing the fork to blow through..Note: depending on the type of fluid also effects CO position)

5) also if the rear shock is not matched with the front it can have a effect on the front..and vise versa

These are just some suggestions too look at..Also geometry plays a difference in the WR and the YZ... So this is quite possibly why they worked on the wr

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Personally I see a few issues here.

1) at 210 LB your spring rates is off

2) your reb setting is way too stiff

3) go to the EPNP

4) suggest changing the Co position further down the stack on the base.( combinaton of all the above is allowing the fork to blow through..

5) also if the rear shock is not matched with the front it can have a effect on the front..and vise versa

These are just some suggestions too look at..Also geometry plays a difference in the WR and the YZ... So this is quite possibly why they worked on the wr

agreed, however id lighten the mid as well as the reb.

maybe 20/20/18/16/14/11/11

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agreed, however id lighten the mid as well as the reb.

maybe 20/20/18/16/14/11/11

:worthy:

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Tanks +++

Gona order 10N ics and i`ll guess heavier fork springs, any idea how hard i should go, the 0,44s that worked so well on the 450 is to soft when doing the shimming softer i`ll guess. (for the 450 that is).

I got the reb stack from a build sheet, a Davej pdf.

I use a 5,5kg rear spring on the yz250f and got good sag numbers 29/103mm.

Rob are you the one a usually order from? up north..

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Hi guys any suggestion on the reb stack ? less hi or low speed or should i do both. How much, like stock ?

20.1

20.1

20.1

13.1

18.1

16.1

14.1

12.1

10.25

10.25

thanks Henric

You have a wery small gap for the fork bleed on the base, maby you have to change those 2 x 11 x 0,25 to 11 x 1,43

i looked closer on the base and i saw that there was a 1,43 already..

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Hi guys any suggestion on the reb stack ? less hi or low speed or should i do both. How much, like stock ?

20.1

20.1

20.1

13.1

18.1

16.1

14.1

12.1

10.25

10.25

the example i gave above is stock, the rebound i have is as follows

20.1

20.1

20.1

20.1

13.1

20.1

18.1

16.1

14.1

13.15

13.15

13.15

13.15

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the example i gave above is stock, the rebound i have is as follows

20.1

20.1

20.1

20.1

13.1

20.1

18.1

16.1

14.1

13.15

13.15

13.15

13.15

I would lean toward the stock reb settings if it were me. Also what springs did you end up with in the front?

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I would lean toward the stock reb settings if it were me. Also what springs did you end up with in the front?

Gona try 0,44 that worked well on the 450 but having a pair of 0,45 if the 0,44 are feeling to soft.

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