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  1. #1
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    Marzocchi Junior T Air Mod questions

    I have a 2004 Marzocchi Junior T that is way too soft. I have heard rumors of replacing the top cap on one leg with an air cap, then just add air to increase stiffness. A few questions about this:

    1) What do I have to remove in the leg I modify to make this happen?

    2) Do I need any sort of spacer inside the fork? I have heard that you need a 1/2" spacer to stop the SSV rod from hitting the air cap. True? Or is all this stuff removed anyway?

    3) Do I still put oil in the new air leg?

    4) Where can I get an air cap?

    5) Does it really work? Or is this just a bad internet idea.

    I'm about to order new all new seals and any other rubber parts that can be replaced, etc as well as new shock oil and a though cleaning of everything. Just did all this with my Fox RLC (as well as machining a custom travel spacer) so I am very confident none of this is beyond me. Just want to make sure I have everything I need to finish the project before I start so my bike isn't down for any extra time and I can go ride!

  2. #2
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    The air mod works. Did it on my '04 Super T since I had all the parts on hand. Just replace one leg's cap with an air cap. I think I had to stick some plastic washers in there to space it out and preload it- you lose the preload knob on that side. Everything else stays the same. It did make the fork feel notchy and weird and not want to get full travel and I personally did not like it.

    I've got other '04 Marz forks that are coil spring and came factory with air preload, and they all work best with zero air.

    IMHO if the spring is too soft, you should really just get a new spring. Your idea of a full rebuild is a very good one also.

  3. #3
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    What do you mean by "I think I had to stick some plastic washers in there to space it out and preload it"... Did you?

    How was it nochy? Did it seem like you were forcing pockets of air through the oil system?

    Thanks for the reply, trying to get as much information as possible before pulling it apart.

    The way I see it: unless it has an air piston, the bushings and oil seals are the only thing stopping the air from leaking out, in which case it will because they are not designed to stop air pressure; just force oil through a spring-governed hole. Sounds like I'm going to have to pull in apart and deal with the downtime. I'll try and upload pictures when I do.

  4. #4
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    Quote Originally Posted by mr2peak View Post
    What do you mean by "I think I had to stick some plastic washers in there to space it out and preload it"... Did you?

    How was it nochy? Did it seem like you were forcing pockets of air through the oil system?

    Thanks for the reply, trying to get as much information as possible before pulling it apart.

    The way I see it: unless it has an air piston, the bushings and oil seals are the only thing stopping the air from leaking out, in which case it will because they are not designed to stop air pressure; just force oil through a spring-governed hole. Sounds like I'm going to have to pull in apart and deal with the downtime. I'll try and upload pictures when I do.
    The air cap has no preload assembly so you need something in there to take up it's space and apply a little load on the spring. Plastic washer, piece of wood, whatever. Haven't even touched the thing since 08? 09? so I don't remember for sure. Take off the cap and you'll see what I mean- air cap is flat on bottom, preload cap is not. I think. I was splitting time between a Super T, z150, Drop off, and Z1 (ex Marz whore here) back then so it's a little fuzzy.


    'Notchy' as in 'felt like ass'. Really. This part I definitely remember. The air does not do any damping at all- not even on an air fork. It's just there to act as a spring. The air pocket sits on top of the oil. In a coil fork, adding air is supposed to let you fine tune your sag. With my old Marz forks, it screwed up the spring curve and prevented full travel. The oil seals could hold the pressure fine but I don't think they like it much, hence extra stiction and loss of small bump compliance. It all made sense on paper but when I actually did DH runs all my forks felt best with very little or zero air in them.

    This is all just my opinion anyway. Try it for yourself because tastes differ pretty widely on suspension.

  5. #5
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    Thanks for the detailed answers. Sounds like I should just drop the money on a stiffer spring. Too bad didn't want to drop more money on this aged fork.

  6. #6
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    Bad idea. Because the coil spring chamber is not sealed off from the lower leg chamber, you're introducing air pressure that is being retained by your dust seals, which they are not meant to do. There will be high probability that on big hits you can blow your dust seals clear out of the fork leg, or at least blow the inner seal.

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