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  1. #1

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    mx comp air pressure question

    I have an 04 MX comp120mm w/ETA on a Devinci Guzzler. I read and have been told how plush this fork is. I set the psi where its recomended(50psi as Im 200 pounds including hydration pack etc.) and it rides like a rock on rooty trails. it takes big hits well but its very stiff on mid to small bumps. in order to get the "plushness" i hear about I have to drop the psi to 35 and it climbs like a marshmallow even in 30mm mode. I have over 200 miles on it and many more than 20 hours.stiction is not a problem but compression is. am I setting it wrong?am I expecting too much?can anyone help me with this please? thanks for the help. Ive always wanted a bomber due to reputation, so Im thinking Im setting it up wrong. the TALAS rear shock is doing as well as advertised after some tweaking so I think its a setup issue but am baffled to the solution

  2. #2
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    Quote Originally Posted by markthetaselmore
    I have an 04 MX comp120mm w/ETA on a Devinci Guzzler. I read and have been told how plush this fork is. I set the psi where its recomended(50psi as Im 200 pounds including hydration pack etc.) and it rides like a rock on rooty trails. it takes big hits well but its very stiff on mid to small bumps. in order to get the "plushness" i hear about I have to drop the psi to 35 and it climbs like a marshmallow even in 30mm mode. I have over 200 miles on it and many more than 20 hours.stiction is not a problem but compression is. am I setting it wrong?am I expecting too much?can anyone help me with this please? thanks for the help. Ive always wanted a bomber due to reputation, so Im thinking Im setting it up wrong. the TALAS rear shock is doing as well as advertised after some tweaking so I think its a setup issue but am baffled to the solution
    Have you checked the oil levels? Marzocchi is infamous for shipping their forks with too much of it.

    _MK

  3. #3

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    Quote Originally Posted by MK_
    Have you checked the oil levels? Marzocchi is infamous for shipping their forks with too much of it.

    _MK
    ROGER THAT. It probably has as much oil as you can possibly fit in it. That is what I have seen on the last two new MXs I have been inside.

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    ummmm. oil? my last fork was an elastomer. sorry to sound so dumb but on this I am. I spoke with the shop I got the bike at yesterday and they said bring it back cuz they want to know too so they are going to tweak on it. check the rebound on the coil side,etc.I got the book out and was cross eyed at the possibilities and since its still under the free check and adjust warranty I figure Id let them do it. thanks for the replies. I will try to be there when they tear into it so I can see how to do maintain it

  5. #5
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    Yeah, the fork is one side air and one side coil. There is oil on both sides. The oil helps keep things lubbed and moving smoothly, also offering a coushion in case you bottom out, that way you don't damage the stanchions. On the coil side, the oil also travels through a cartridge, on the way up or down it helps define fork's compression and rebound characteristics. On the air side of the fork, air makes the fork less easily compressible, helping fine tune the fork for the rider's weight. This can also be done by changing the viscosity of the oil, but that doesn't sound like an easy task, compared to changing air pressure, does it?, it also affects rebound. When there is too much oil, the cushion it provides is met by the traveling stanchion too soon, and since oil is not compressible, it limits the travel of the fork.

    _MK

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    thanks for explaining it so I can understand. thats what oil bath is huh?I looked at the book and it said "if" there was an internal rebound it would look like; and then a picture.I took the ETA cap off and it did not look like the book so I just put the cap back on. the book says the MX comp w/ETA has an internal rebound but there is nothing that I have seen on the fork that looks like anything in the book. so how does one go about checking the oil level? is this a major undertaking? as I said before my last fork had an elastomer,so it was easy to clean and work on. I have come to the conclusion that the compression is ok but the rebound is too fast by judging the action against the TALAS rear shock and how it rebounds. its like it rebounds too fast. should I just let the shop I got it from take care of it? I like doing my own work but believe this one is over my head and dont want to mess up the fork.

  7. #7
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    rebound

    It actually is very simple to adjust the rebound. Your fork should have come with a long hex rod. You have to unscrew the eta knob and I think that you will also have to get a 21mm socket (i got a 2003 model) and unscrew the cap. This will open up the shock. You will then insert the rod into the fork and you should feel it catch. just turn the knob a little, I really am not sure how much you will need/want to to achieve desired rebound, and screw the top cap back on. Ride it, see if it it still to fast, or too slow, and repead the procedure until you get it just right. To check oil levels, unscrew both caps on both sides, compress the fork all the way, the spring will come out on the left/eta side. I've heard that you will need to remove spring/eta cartridge for proper oil level check, however, if you'll just take a syringe or a dropper and suck up a little oil from both sides, screw it back together, see how much travel you get, and if it bottoms out, just add more back it, if it still feels hard/doesnt' get full travel, take out a little more. On the air side, actually, the oil should be 50mm or so from the top of the leg, you should search the forum, however, I dont' remember off the top of my head, and the subject has been discussed.

    _MK

  8. #8

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    MK you da bomb!!!! thanks a bunch. I will try it Fri. as Im off of work so Ill have some time to tweak on it. thanks again

  9. #9
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    Here is a good link for fork information

    Try this link, might have some good stuff there...http://manualer.happymtb.org/

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    thanks for the link. that confirmed with pictures. I had to go out and purchase a 21mm socket to get the cap off and it started raining again so I'll have to tackle it in the AM tomorrow which works well since Im riding a slow ride anyway. thanks again. I'll post the results

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    uh oh

    I got the cap off this morn and THE WHOLE DAM THING CAME OUT.there was nothing except the ETA unit attached to the spring as one. the cap was mated to the rod . I just put the cap back on and am going to take it to Cobblestone where I bought it and let them figgur(intentional mispell) it out. thanks for all the help to all. I did learn what the inside of both legs looks like so theres the lemonade factor. I tried the air side just for kicks, after letting the air out. nothing there either. like I said I now know what the guts of a MX comp look like

  12. #12
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    That's not as bad as you think. You just didn't do it right. You need to keep the right leg cap on, only unscrew the left cap. You also have to unscrew the ETA knob, prior to undoing the 21mm nut. If you unscrew both caps, the fork will dive all the way in, since there is nothing holding it up. If you keep the right leg closed and left leg undone, the fork will stay extended and you can adjust the rebound.

    _MK

  13. #13
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    wrong side

    Hi there,

    unfortunately I saw this thread too late. The provided instructions were wrong, at least for the 2004 model forks.

    For the 2004 models rebound adjustment is found only in the right hand side leg!!!

    To adjust the rebound, first take off the topcap. Afterwards let all the air out of that leg. Using a 21mm socket spanner, remove the lockcap with the valve.
    Insert the hexagon rod provided in the stanchion being careful to center the notch
    of the adjusting screw. It's sometimes a bit tricky to find the screw at the first attempt.
    Adjust rebound to your personal preferences.

    Here you'll find instructions with pictures, just look for 2004 mx comp eta.
    http://manualer.happymtb.org/marzocchi/

    Kind regards.

  14. #14

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    I used that link.its a coollink. I did the left and right sides at different times so I didnt have the bottom out problem. the left side just came out when I pushed down. I put it back then I tried the right leg. maybe I just didnt look real well at the right side due to not thinking it was going to be there and frustration at being so unedumacated with this new technology. I will take a better look at the right leg this weekend. words cannot express my gratitude at yalls patience in this regard.as I said before Im getting to know what the inside of this thing looks like. thanks again. and I had not yet gone to the shop yet so its not too late. I know they can do it I just dont want to lose the riding time by not having a bike for a couple of days and like I said in the start I like to do my own work for the knowledge and fun

  15. #15

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    AHHHHH SUCCESS !! I had some time to fiddle today so I took the cap off the right leg and stuck the rod down in there.after a little fumbling I found what I was looking for.it looks as though there is a range of about 5 turns from full speed to super slow. I turned it 1 turn counterclockwise and rode over an area near me loaded with bricks and large rocks. it was almost as plush as the rear. I will hit the trails asap and try it. I talked to the rep at my LBS and he suggested if its a little mushy on the compression but just right on the rebound to turn the rebound about 1/2 a turn more and increase the air on the fork about 5-10 psi and they should hook up well together. thanks a bunch for all the help

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