950 SE rear shock.

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by Pitster, Aug 17, 2016.

  1. charlie264

    charlie264 Long timer

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    I'm being a bit thick. The shock I have appeared to have two 3.5mm washers, one was so rusty the internal diameter confused me. So it looks like 2 x 48 on the parts fiche, so for the 265 spring I need one 48 and one 46?
  2. alongat

    alongat Fesh Fesh

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    Correct Charlie.
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  3. charlie264

    charlie264 Long timer

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    What oil weight Alon?
  4. alongat

    alongat Fesh Fesh

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    Pretty sure it calls for 7.5 but I know some people use 5. I just went with the spec’d 7.5
  5. charlie264

    charlie264 Long timer

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    Things not looking good, seems whom ever last had the shock open stripped/crossed threaded the end nut. Pretty sure the shim stack was wrong too...
  6. alongat

    alongat Fesh Fesh

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    Uh-oh...
  7. charlie264

    charlie264 Long timer

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    Shaft is scored too.....FFS. :kboom
  8. bigborett

    bigborett Hipster

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    Never posted this I don't think.
    The one I got was 2007 model with the short reservoir. The 215 mm travel one.
    Had the shock travel lengthened to match the standard SE and ran the spring that came on it (150-225) with a spacer. No need to go the longer spring.

    I'm around 97kg without my gear. With an unloaded bike but gear on I could not quite get down to the required sag, but as I virtually never ride with no luggage or tools or spares gave it a go. Leaves me room to crank it up for loads. Seems great. Takes reasonable jumps over erosion mounds with ease, could jump much more if my shoulders could be relied upon, good on corrugations, rocks, pretty much everywhere. Don't feel that I need to go softer, it is still quite compliant. Mind you RaceTech had had a go at this shock before I got it.

    Great mod.

    20190226_192430.jpg 20181213_191531.jpg
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  9. anydavenow

    anydavenow Long timer

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    Do you have any details on the spacer you used @bigborett? Looking at taking my ADV from 210mm to 250mm with a pair of SE cartridges I've picked up for the front end.
  10. bigborett

    bigborett Hipster

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    Sorry, no.
    I gave the suspension mob the SE and adventure shock and said give me the same travel.
    I believe they machined one to suit.
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  11. alongat

    alongat Fesh Fesh

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    What’s important to remember when extending the length / travel of a shock is that it’s not just about spring length. Yes, you can reuse the 215/225mm length spring and add a spacer above or below it to achieve a longer overall length but you won’t be able to unless you also address the internal spacer that KTM calls a shim (not to be confused with the valving shims). This internal spacer’s thickness determines how much the rod will extend beyond the shock body and so the thicker the spacer is inside, the less the rod can extend. The standard Adv shock comes with a spacer that’s about 25mm thick. The S / R comes with one that’s about 3mm thick. That means the shock rod extends out 22mm more on the S / R shock

    If you install a longer (S or R 255/265mm) spring onto an Adv shock without changing this internal spacer, all you will do is end up installing a spring with a boat-load of preload but you will not get the extended length if that’s what you’re after.

    Does this make sense?
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  12. bigborett

    bigborett Hipster

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    The internal and external spacers were altered to achieve the required travel and spring preload.
    The external spacer is only to maintain the required spring preload once the shock travel is extended via the altering of the internal spacer.
  13. anydavenow

    anydavenow Long timer

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    Copy that @alongat, makes perfect sense.

    I'm familiar with the internal spacer that limits the extension of the shock itself. As I understand it, this is how it works:

    Spacer.jpg

    As you've explained, counterintuitively a larger spacer gives less travel.

    From what I can tell, based on earlier model fiches which give more detail on the shock, I'll need:

    91210028 SPRING 140-255 (62) D=15,0
    50180401 SHIM REBOUND H16 '03

    Current spring is 150-255 though not sure whether I need that rating with the extra length added. None of the "high travel" 990s seem to run a 150. Maybe a question for a tuner.

    Anyway, apologies for hijacking the thread for a slightly different project. My 990 one over here didn't get much love!
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  14. skuikka

    skuikka Been here awhile

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    255 "shim" on the shaft and 230 or something like that on top.

    Attached Files:

  15. alongat

    alongat Fesh Fesh

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    Yes - exactly. As for spring rates, you’ve got an Adv which is a bit heavier than an SE and I don’t know how often you carry a passenger and / or heavy luggage (mind you, that’s what the preload adjustment is for)...the long length springs (265 and some 255) were / are available from WP in 130/140/150 rates. 150 is a popular rate on the advs but I’d say it also depends on what you’ve got up front as well.
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  16. charlie264

    charlie264 Long timer

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    Anyone know of a shim stack database for these shock, or got one apart, who can confirm something for me please.
  17. skuikka

    skuikka Been here awhile

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    Sorry, it is in Finnish. Pohja reb=PDS piston rebound, pohja comp=PDS piston comp and so on.
    I assume this is stock valving. 2004 Adv, short.

    Attached Files:

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  18. charlie264

    charlie264 Long timer

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    Thanks will have a look latter.
  19. bobone

    bobone Been here awhile

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  20. anydavenow

    anydavenow Long timer

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    Performance-wise the rear has been fantastic with a decent amount of luggage (think RTW) on the bike, so I'm keen to retain that.

    q6+YVlunRsiC3d3cVcAaMQ.jpg

    I just wondered whether extra length should be compensated for by reduced stiffness (in general).

    The front has .64 springs in it which is great for full Safari tanks (43 litres) but I think they're a bit on the heavy side and traction suffers sometimes, so when I go with the SE cartridges I'm planning to lighten those a bit. Still way better than stock offroad now, don't have to baby the front anymore. Thought I do seem to get more pinch flats!