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  1. #1
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    KS i900 FIXED. It is FULLY rebuildable at home.

    Number 1 son and I pulled the KS i900 apart the other day - and we mean A-P-A-R-T. Separated all 3 pipes (actually 2 are pipes, the other is a "plunger" rod).

    The original motivation was to replace the stupid roller bearing under the red coller (that doesn't roll, as the shaft moves perpendicular to the rollers - der!). Much better to put a brass bushing in there - so out comes the lathe. New bushing in - BUT - 3 hrs of trying to reassemble the inner shafts, spraying oil all over kitchen ceiling, just cannot get it together.

    Then, someone PsyCro over on this thread
    Ummm...Help, my KS has turned against me.
    mentions that he has seen a tiny pin-hole inside one of the indents used to turn an alloy sealing cap. We check it out, and THIS IS THE SECRET!

    Sorry for the lack of step-by-step pics - but we were so excited to get it back together (and so oily) that we just kept going, and don't really feel like pulling it apart again right now. We have labelled the pics as best we could - hope these are helpful.

    Do not listen to those who say the KS i900 is not user serviceable - it is. Works better than it ever did new now that it has a proper bushing, AND we can now tailor the speed of the seat raise because now we know where to pump the air!

    Major props to PsyCro for pointing out the pin-hole - we would never have seen it.

    Directions as follows:
    1. put the circlip into the top of the "middle" tube (the one the seat eventually clamps into)
    2. put the "plunger" into the middle tube and place it at its most extended position. Put the black ring with it's inner and outer o-rings on the outside of this shaft and the alloy cap with the hole in it over the plunger.
    3. fill the middle tube (the one with the plunger in it) to the very top with 5wt oil.
    4. place the alloy cap that buts up against the circlip into the top of the shaft filled with oil, this will seal this chamber.
    5. slide this assembly into the main shaft untill the alloy cap has pushed up against the circlip.
    6. do up the silver alloy cap that has the pinhole in it.
    7. to pressurize the chamber, be imaginative. I used a compressor tip for inflating soccer balls, wrapped some tape around it to seal, and jammed it in the indent with the pin-hole. We put about 120psi in (with the shock pump) but I'm not entirely sure, put in enough so the shaft extends by itself when you press the button on the top cap. (the one near the circlip)
    8. put the rest of the post back together, bearings, lube etc.

    Sorry for the lack of pics, we tried to label things as best we could.
    Now go tear 'em apart! What do you reckon?
    Attached Files Attached Files

  2. #2
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    Nicely done mate. Buzzy's slick honey works like a charm.

  3. #3
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    I saw a post somewhere that had detailed step by step instructions about how to rebuild this seat post. I can't remember if it was on this forum on on KS's website but there's one out there that has very good pictures and very detailed instructions.

  4. #4
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    If it's the one below, this guide above looks to go alot further

    http://www.watermanatwork.com/Land/C...jSeatpost.html

    Many thanks and props to the OP, you may have help me out no end

    Anyone have a source for getting brass bushings to fit?

  5. #5
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    Quote Originally Posted by wpuk
    If it's the one below, this guide above looks to go alot further

    http://www.watermanatwork.com/Land/C...jSeatpost.html

    Many thanks and props to the OP, you may have help me out no end

    Anyone have a source for getting brass bushings to fit?
    Yeah, that's the one I was thinking of.

    I put the Buzz's Slick Honey on mine and have ZERO stiction now. I don't know why you would want to redesign the bushing if it works as is. Try the BSH before you go to all this trouble.

    A full rebuild may be necessary eventually though so this post might make a good bookmark. I protect my post with a seat bag so I'm hoping it will give me many years of operation without the need for a rebuild.

  6. #6
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    My post was just fine - until I had a pedal-strike with the seat up, and all my weight on it. The ball bearings chunked into the guide slots - and the post was never the same again. When we pulled it apart, we found that there are 6 guide slots, and only 3 are used. On reassembly, we just used the other three guide slots. Back to slippery-dippery

  7. #7
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    It awefull that theres no detailed instructions for field service of this post. Whats the big secret? What are they afraid of? I work on forks all the time and I can get details on most all quality forks to rebuild. You might need special tools but if you work on them a lot then you buy them.

  8. #8
    catracho in aztecaland
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    Quote Originally Posted by ARCSAT View Post
    It awefull that theres no detailed instructions for field service of this post. Whats the big secret? What are they afraid of? I work on forks all the time and I can get details on most all quality forks to rebuild. You might need special tools but if you work on them a lot then you buy them.
    I'll say it has to do with the fact that there is no valve to let the pressure in the chamber out, so you need to risk blowing something in your face or garage if not disassembled properly. Definitley it was not meant to be user-serviceable.

  9. #9
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    Has anyone found a source for rebuild parts for this post. My post no longer holds the seal between the air and oil chambers after a rebuild. After my latest rebuild I got less than a ride before the post began to sag.

    Attempts at contacting Kind Shock in CA have been frustrating to put it politely.

    Universal Cycles has 2 parts available. A mystery o-ring and the DU bushing. The o-ring is very small and I suspect it belongs on the inner most shaft. I have reservations this one o-ring will solve my issue. A full o-ring kit would be preferable.

  10. #10
    aka dan51
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    This thread rules!
    My post started doing the 1" drop last week during a road trip.
    I found this thread and thought I'd give the rebuild a shot.
    I went at it slightly differently, but the end result is a post that works perfectly again and I didn't have to wait 2-3 weeks for a factory fix.
    Being able to service it at home now bumps this into the #1 place for adjustable seatposts.

    After taking it apart and seeing how it works, I am pretty sure the post busted because someone picked the bike up by the seat with the post down. I will never pull up on the seat again when it's in the down position.

    I rebuilt with 5wt fork oil, but will use 2.5wt next time. The oil that came out was thinner than the 5wt I had.
    Those who know, ride a Mojo AND a Mojo HD.
    Quadzilla
    Quote Originally Posted by benja55
    Ok, whatever, cold water on my bike boner right there.

  11. #11
    Dirt Bike Craig
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    Quote Originally Posted by d-bug View Post
    After taking it apart and seeing how it works, I am pretty sure the post busted because someone picked the bike up by the seat with the post down. I will never pull up on the seat again when it's in the down position.
    Just curious how this would "bust" it. I've done this more than once with no seemingly bad effects...
    Check out my photography on RedBubble http://www.redbubble.com/people/fmxdbc

  12. #12
    aka dan51
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    Quote Originally Posted by FMX_DBC View Post
    Just curious how this would "bust" it. I've done this more than once with no seemingly bad effects...
    When the seat is pushed down, the oil gets moved from one tube to another through a valve at the top of the post (lever activated). When you pull up on the seat, it creates a vacuum in the chamber where the oil was. If a few air bubbles get by a seal and get into that oil chamber it becomes "busted". It's like getting air in your hydraulic brake lines. I've picked mine up a few times by the seat and not had any problems, but the 3 times I've had problems I know the bike was picked up with the seat down. Weird thing is that the problem did not come up immediately after picking it up by the seat. Which makes me think the air gets in there, but may not get into the main chamber right away.

    I could be totally wrong about this, but after looking at the internals for 2 hours I don't think I am.
    Those who know, ride a Mojo AND a Mojo HD.
    Quadzilla
    Quote Originally Posted by benja55
    Ok, whatever, cold water on my bike boner right there.

  13. #13
    Dirt Bike Craig
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    Very good to know, thanks! I'll try to avoid doing that from now on
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  14. #14
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    I sent mine in and they turned it around same day!

  15. #15
    aka dan51
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    DISCLAIMER - I do not work for KS, this is not an officialy supported how to. I gathered info from other users in this thread who figured it all out, I just took more pictures.
    If you try this and screw it up, it's on you. I won't be held responsible for anything.
    Hopefully this will help some people out, or get KS to put out an offical guide.
    *Avoid scratching any of the surfaces, as this may allow air to get into the system.
    *Clean everything before reassembly.

    Stuff needed for rebuild.
    -2.5wt suspension oil
    -shock pump
    -ratchet and 7/16" socket
    -slick honey
    -small funnel
    -C-clip pliers with angled ends
    -ball inflation needle
    -heat shrink tubing (for the inflation needle)

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    Last edited by d-bug; 07-26-2012 at 08:36 AM.
    Those who know, ride a Mojo AND a Mojo HD.
    Quadzilla
    Quote Originally Posted by benja55
    Ok, whatever, cold water on my bike boner right there.

  16. #16
    catracho in aztecaland
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    Quote Originally Posted by d-bug View Post
    DISCLAIMER - I do not work for KS, this is not an officialy supported how to. I gathered info from other users in this thread who figured it all out, I just took more pictures.
    If you try this and screw it up, it's on you. I won't be held responsible for anything.
    Hopefully this will help some people out, or get KS to put out an offical guide.
    *Avoid scratching any of the surfaces, as this may allow air to get into the system.
    *Clean everything before reassembly.

    Stuff needed for rebuild.
    -2.5wt suspension oil
    -shock pump
    -ratchet and 7/16" socket
    -slick honey
    -small funnel
    -C-clip pliers with angled ends
    -ball inflation need
    -heat shrink tubing (for the inflation needle)
    d-bug you da' man! Now, I having done this procedure quite a few times coming from zazzique pictures (wish I'd had yours before ) if there has been air moving into the oil chamber then the seals or the IFP have something wrong. That is what my understanding came to.

    You are implying that if you accidentally pull the seat and get air past the IFP to the oil chamber, then rebuilding is all that you need? or that definitely the seals or IFP should be replaced?

    P

  17. #17
    Dirt Bike Craig
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    Nice writeup with great pictures! Thanks!
    Check out my photography on RedBubble http://www.redbubble.com/people/fmxdbc

  18. #18
    aka dan51
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    Quote Originally Posted by pabloquintana View Post
    d-bug you da' man! Now, I having done this procedure quite a few times coming from zazzique pictures (wish I'd had yours before ) if there has been air moving into the oil chamber then the seals or the IFP have something wrong. That is what my understanding came to.

    You are implying that if you accidentally pull the seat and get air past the IFP to the oil chamber, then rebuilding is all that you need? or that definitely the seals or IFP should be replaced?

    P
    I think it could be either seals/IFP going bad, or just air getting in somehow. If the problem happens again soon then the seals/IFP likely need replacing and it should be sent to KS.
    I tend to think of this process like a brake bleed. Doesn't mean the brakes are bad, just that air got in and needs to be removed to return to optimal performance n
    Those who know, ride a Mojo AND a Mojo HD.
    Quadzilla
    Quote Originally Posted by benja55
    Ok, whatever, cold water on my bike boner right there.

  19. #19
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    Good job, you know the number or reference of the quad-ring smaller for KS 950IR?

    greetings

    Duarte Guedes

    PORTUGAL

  20. #20
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    Great job d-bug.
    I don't think you could be more helpful!

  21. #21
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    what a great thread! I have a problem though, I can't get the baseplate off. just won't freaking spin.

  22. #22
    aka dan51
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    Quote Originally Posted by driveroperator View Post
    what a great thread! I have a problem though, I can't get the baseplate off. just won't freaking spin.
    There are two base plates, one internally, and one externally (on the lower black tube).
    You do not need to remove the base plate on the lower black tube. That f#@cker is hard to get out, and never provides anything when out.

    The base plate pictured above turned with little effort for me.
    Those who know, ride a Mojo AND a Mojo HD.
    Quadzilla
    Quote Originally Posted by benja55
    Ok, whatever, cold water on my bike boner right there.

  23. #23
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    Quote Originally Posted by d-bug View Post
    There are two base plates, one internally, and one externally (on the lower black tube).
    You do not need to remove the base plate on the lower black tube. That f#@cker is hard to get out, and never provides anything when out.

    The base plate pictured above turned with little effort for me.
    I see. attention to detail. apparently I am lacking. thanks

  24. #24
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    So I bought a used post that did work not thinking that I could fix it. So I just tried doing this last night and I have a few questions the plunger rod has a dual lip seal/o-ring near the end then it has another groove that looks like is intended for another seal or o-ring, am I missing a part here or is this how it is intended to be. Also the plunger is not solid on the end like the OP's it is hollow for an unknow depth how is this addresed when trying to reassemble and making sure not to get any air in the small tube. Is there a secret to getting the small tube (the one the plunger rides in) through the black ring, even with it centered it is very difficult to get through. So anyhow once I got it back together it was better but still not right. The post acts like the valve (on top of the post used to raise and lower) is not sealing. Is will slowly rise on its own and can be compressed or extended by hand without activating the lever/valve. Any suggestions on what to look for.
    Thanks

  25. #25
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    Double Post

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