Attacking my own KTM WP PDS shock

Discussion in 'The Garage' started by VABDet, Mar 5, 2016.

  1. yu130960

    yu130960 Adventurer

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    Good point. I will re-bleed, re-set and then wait for nitrogen charge.
    #81
  2. VABDet

    VABDet Is it dirty? I'm in...

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    Theoretically if everything is sealed and set it should not matter. The charge should push the piston back in and seal head out since you can't compress or stretch the volume of the oil?

    In my theory that's probably as well the reason you have to set the nitrogen piston a little lower so it doesn't hit the top when the seal head fully seats?
    #82
  3. Yinzer Moto

    Yinzer Moto aka: trailer Rails

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    There are a lot of tools that factory service manuals call out as nessary to do a job but with a little care, you really do not need them. They are needed for a mechanic who is getting paid to do the job quickly.
    #83
  4. VABDet

    VABDet Is it dirty? I'm in...

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    We've been mostly talking about the need or no need to align the 2 pistons and the seal head.
    #84
  5. yu130960

    yu130960 Adventurer

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    Received my Racetech Nitrogen Charging tool and charged my shock. Thanks to VABDet for the tip of leaving everything under pressure until the shock sealing bolt w/ oring is tightened. Couldn't believe how easy it was and can't believe my dealer wanted to charge me $50 just for a charge. Charged the shock to 180 PSI per Racetech's recommendations and bolted the shock back in the bike. I love installing PDS shocks in 15 seconds.

    I am now turning my attention to dialing in the carb and won't be back to the shock until after I have had a chance to try out my current valving.

    Thanks again to VABDet for sharing ideas and trouble shooting.

    Total spent on tools for me in CDN funds

    $150 for filled Nitrogen Bottle 55cf
    $50 for Nitrogen Regulator
    $20 for hose and fittings
    $60 for T1214 Piston Alignment Tool
    $20 for 18mm Ebay Bushing driver kit (Kit came with all sizes)
    $100 for Vacuum Pump
    $100 for DIY Shock Bleeder

    $500 CDN

    Racetech Dealer wanted $180 to do the revalve.

    Of course, now I can service my own shock every 25 hours and figure I am going to break even at the 2nd or 3rd service, sooner if I determine I need to re-valve my Racetech gold valve.

    As a bonus, I rebuilt my mountain bike shock which I though was toast.
    #85
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  6. VABDet

    VABDet Is it dirty? I'm in...

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    Congrats on your successful completion!! :thumbup:thumbup:thumbup

    I figured I deserved some distraction after all that shock work and tested the shocks on someone else's bike :ricky
    #86
  7. xxexx

    xxexx n00b

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    Hi there, thanks for the good information, i have 2 questions:
    1. how did you get the correct distance (piston depth) for your Nitrogen Piston Setting tool?
    2. did you consider drilling and tapping the reservoir to put in an schrader valve (e.g.
    Fox Racing Shox Schrader Valve Assembly)
    with a thread and fill it up with air? (80% nitrogen anyway)

    #87
  8. VABDet

    VABDet Is it dirty? I'm in...

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    The distance is in the repair manual, and I use a caliper to slide the O-ring in the right position

    [​IMG]

    About the nitrogen, I was thinking at some point to use air instead and go the schrader valve route but then I have access to free-to-me nitrogen. Either way, if you get the adapter it uses a schrader valve as well. I think filling it with nitrogen you can get done at any better equipped tire place.

    As a quick fix air will probably do fine, but it contains more moisture and expands more than nitrogen under heat which will be created on longer rougher rides. Would I really notice it? I have honestly no idea.

    Just remember, if you set the piston distance and you are ready to fill it with nitrogen, do not compress the shock. It will squeeze the oil in the non pressurized reservoir and mess up the piston position.
    #88
  9. xxexx

    xxexx n00b

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    VABDet - you are the man - i totally missed that in the manual - thanks for the info and the tip to not compress the shock while setting piston distance.

    will try to put in a valve. THX and all the best.
    #89
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  10. xxexx

    xxexx n00b

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    ok, just so i get this straight: first i should adjust the o ring on the piston setting tool to 106mm, then i should insert it so that the o ring has a distance of about 10mm from the screw cap? why not just use a caliper, set it to 96mm and shove it all the way in?

    BTW, schrader valve was made by removing all the rubber from a car valve with a lathe, then turning a m10 thread onto a short piece of aluminum and inserting the valve into the aluminum "screw" and fixing it with super glue - sorry no pictures. I put a o ring onto that, taped and cut a thread into the reservoir and screwed it in together with chinese screw glue.

    To remove the reservoir, i made a tool out of a steel iron and 2 M3 steel screws (distance 33mm), then heated the bottom of the reservoir and with some force it did unscrew.

    Dont forget to consider the height of the schrader valve vs. the original valve and recalculate the insertion depth acordingly.
    #90
  11. VABDet

    VABDet Is it dirty? I'm in...

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    Congrats on your successful schrader valve conversion.

    That setting tool is a skinny metal pin, I actually broke my first DIY plastic setting pin because the separation piston is kinda hard to push up/down. I guess abusing a caliper for this is nothing a manufacturer would recommend :D I didn't even have a screwdriver skinny and long enough to make it in that deep. You will see how it goes bleeding that last excess oil out in order to get the piston in its final position for the nitrogen fill. Depending how you filled and vented your shock be sure to double check that your seal head is in the right position as well (all the way out).
    #91