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  • Oil level question for Marzocchi 55 TST2 damper
  • Premier Icon DiscJockey
    Free Member

    I’ve stripped down and rebuilt my 55 ATAs. I took the rebound/compression pistons out the TST2 cylinder to check o-rings etc.. all looks like new still. I then refitted it, leaving the top cap unscrewed, and squirted new 7.5W oil down into the lower, as per spec.

    Question is, how will oil get into the TST2 cylinder ? There’s no info anywhere about oil levels within the cylinder. Surely there won’t be any damping if there’s only oil sloshing around in the lowers ? 😕

    Premier Icon windydave13
    Free Member

    The link below is for the TST micro, but it might be similar. I tend to fill and then cycle the piston until all the air has gone then top up and screw the cap back on.

    I could be very wrong but it seems to work for me 😆

    Premier Icon hora
    Free Member

    Why not also try this:

    forums.mtbr.com/shocks-suspension/marzocchi-55-tst2-conversion-shim-damping-step-step-410874.html

    Premier Icon DiscJockey
    Free Member

    Thanks Windy – That’s exactly what I was looking for 😛

    So why does Marzocchi not give any advice on oil type and oil levels inside the damping cylinder ? Is the oil supposed to last forever, and therefore we only need to replace the oil in the lowers, hence no mention of damping cylinder oil ?

    Hora – I’d gone through that forum article before, but didn’t see anything about oil levels. Will check again now – it is about 11 pages !

    Premier Icon hora
    Free Member

    Its in there as the shim stack sits in there??..

    I did the mod

    Premier Icon windydave13
    Free Member

    To be fair, my damper cartridge is like a service indicator. It seems to drops all its oil after about 30 hours use, but its so simple to change, I’ve got the full strip of the ATA and TST including new O-rings in the ATA down to about an hour.

    Considering mine are a proper Friday afternoon build they do just seem to keep on going and going 🙄

    Premier Icon DiscJockey
    Free Member

    Result ! I’m getting somewhere now. I do feel rather stupid asking ‘do I put oil in the damper’ but I honestly thought the official service manual would specify the damper oil – it only mentions the oil you pour into the lowers.

    Anyway, I just did the following and it seemed to work:

    Removed the cartridge, clamped it in the bike stand. Removed the rebound piston (top piston). Pulled the compression piston (bottom) all the way down. Poured oil into cylinder slowly, and kept pushing rebound piston all the way in and back out, and repeated this until I could hear the piston starting to squelch in oil. I made a rough estimate that once screwed in, the rebound piston is probably no more than 10mm submerged in oil.

    Refitted the whole thing, and I now have smooth consistent damping all the way through the travel, and no ‘clank’ on top-out.

    Does this sound OK ?

    Premier Icon chrisdw
    Free Member

    Sorry to hijack a bit, but seems like a good thread to ask in.

    I have a pair of 55 micro ti forks. Just come back from windwave with.a full service.but the rebound knob only seems to have any effect on the last few clicks. What do we reckon, not enough oil? Something else? Marzocchi damping internals are all new to me.

    Premier Icon windydave13
    Free Member

    chrisdw – ill be honest, rebound on mine seems to do sweet fa but I’ve snapped the knob off so I never bother trying to adjust it. Even when they knob was still attached I never found the adjustments as significant as what you see with fox.

    Premier Icon DiscJockey
    Free Member

    Next job – rebuild the ATA catridge (new 116 and 114 o-rings in the post).

    Apparently these carts really were a peice of s**t and a good solution was replacement with coil spring. I’m hoping that the main problem will just be air leaking into the upper chamber, effectively creating a -ve zone that prevents rebound to full travel. I reckon mine are stuck down at about 120/130mm currently.

    RE: rebound – my lockout was doing nothing before – now it works 100% following a oil replacement, not that I’ll be using it much given the lovely cushioned ride I’m getting with these !

    Premier Icon windydave13
    Free Member

    I’ve had that. I read something on a different forum about putting slightly oversized O-rings in but this did nothing. I’ve gone back to official Marzocchi ones. I had issues with air leaking from the ATA into the fork leg itself so I ended up with an extra spring. I’ve taken to carrying a cassette tool and a spanner with me to crack the air off if need be mid ride.
    However since the last service and new O-rings they’ve been fine.
    They’re so simple it doesn’t take long to strip clean and rebuild and the orings are pennies.

    Premier Icon DiscJockey
    Free Member

    Thanks Windydave – I’m fairly sure I’ve got air leaking into the fork leg. When I push down, I can hear a slight hissing of air from under the ATA knob. I don’t know if it’s coming through the height adjust spindle, or around the edge of the whole top nut ?

    So when you loosed the top nut while out riding, does your fork pop back up to full travel ?

    Presumably, if air isn’t supposed to get into the top chamber of the ATA cart, it’s normal that it then leaks out of the cart and into the stanchion ? Or does this suggest that I’ve got possibly 2 leaks:
    1) One leak into the top chamber in the ATA cart
    2) Another leak from the top chamber into the stanchion

    I do have another question if you’d be so kind – how does the ATA height adjust work ? Does it wind down a piston to offset the height of the positive air chamber ?

    I can’t actually adjust my ATA travel – the height adjust knob just rests in the top nut via its o-ring, but just spins round. One half of the ATA cart’s spindle has sheared off. It looks like it’s a hollow round cross section spindle with 2 flats that the knob locks onto. Mine has split down the middle. It also seems too low down to engage with the travel adjust knob. The fact it’s broken clearly shows that someone must have tried turning the ATA knob stupidly hard and sheared the top of the spindle off.

    Have you still got your forks ? Would you be able to post a photo of the underneath of your ATA height adjust knob so I can see what it should look like ?

    Premier Icon scruff
    Free Member

    Windawave have always been very helpful replying to servicing question emails.

    Premier Icon DiscJockey
    Free Member

    I’ll give them a try scruff – it might lead to me buying something from them – who knows ?

    Premier Icon DiscJockey
    Free Member

    I got a very good reply from Windwave, so that’s great news. And the coil upgrade is cheaper than I thought it would be, so that’s definitely a viable plan B if I can’t get the ATA cart sorted. I might as well try fitting a new 15 pence o-ring and seeing if that fixes things. From what I’ve read, it is possible to make an ATA cartridge perform well, and arguably that would be better than fitting a coil. Presumably a 55 ATA with coil upgrade (or downgrade depending on how you view this) effectively becomes a 55R ?

    Premier Icon windydave13
    Free Member

    I’ve just loaded the bike into the car for a trip to Scotland but i’ll try take a pic in the morning when I get to work. If the travel has stuck down you need to very carefully release the trapped air in the middle chamber. I had this the other year but a bit more extreme:

    Marzocchi 55 lock down by windydave13, on Flickr

    I just followed this LINKto get the air out but sent it to J Tech after that for a proper service.

    I’ve never stripped the ATA as it works so I’m leaving it well alone.
    If you haven’t got the pdf’s on the breakdown email me and i’ll send them across to you.

    Dave

    Premier Icon DiscJockey
    Free Member

    I removed the ATA cartridge today for the first time and disassembled it. The actual ‘air’ part of it all seems fine. I’m not sure if mine is a standard 2009 ATA, but there is only the one piston at the top, and the Schraeder valve at the bottom is just held by an internal c-ring.

    The problem on mine is with the mechanic travel adjust part at the top. It all seems in a right muddle; the top bolt (the one that takes a cassette lockring tool) screws up and down on the piston shaft, independently to the spindle that the ATA knob is supposed to engage with. The grub screws don’t make contact with this spindle (not sure what they do ?). With the top bolt unscrewed all the way, I get about 145mm travel. With the cartridge fitted and pump up, if I turn this spindle anti-clockwise a bit with some pliers, the travel pops up to about 160mm. The ATA knob can’t engage with the spindle as it has sheared off on one side. Does this sound normal ?

    Premier Icon windydave13
    Free Member

    The grub screws are meant to provide resistance to the ATA knob, otherwise under a hard compression it can start to wind itself down.

    Firstly, are you making sure to fill the bottom chamber first before the top?

    The ATA knob should fit over the schraeder valve and turning that is what adjusts the travel. If you look under the knob, the hole that fits over the valve should have a flat side to it. I wonder if your’s is just spinning on the valve as from what you describe when you adjust it with pliers it works fine??

    When i get mine out the car tomorrow i’ll take a couple of pictures. It was far too cold in the carpark of Glenshee! 😯

    Premier Icon windydave13
    Free Member

    On my mobile to cant embed, but I took some pics of the top of the ATA cart

    http://m.flickr.com/#/photos/windydave13/sets/72157640136663456/

    Premier Icon DiscJockey
    Free Member

    Thanks again Dave – I’m quite sure mine aren’t supposed to have valves at the top and bottom – isn’t that ATA with PAR ?

    Mine only has the air valve at the bottom. Underneath the ATA knob there is a hollow steel tube with flats (currently sheared down the middle) but it’s not threaded, and couldn’t ever have been a valve.

    I’ve now put some photos online showing the cartridge.

    The valve part at the bottom is just that, it’s not a piston, it’s simply a thick disc of aluminium that sits at the bottom of the cartridge tube. The only piston comes down from the top, and is 165mm in length. The tube itself is a bit longer than this. So air pumped in the bottom makes it harder for the piston to move down – there’s nothing more to it that than.

    It’s feasible that this isn’t the original 2009 fitted part – it might be a replacement ATA cartridge from an older or newer 55 fork.

    Premier Icon windydave13
    Free Member

    That makes a bit more sense now, but the bit the ATA knob attached onto to wind it down looks a but fubar’d. Sadly the 2009 service doc doesn’t show how the ATA is made up, but it all should look like the below:


    55_ata_2009 by windydave13, on Flickr

    Could be worth giving James at J-Tech a shout. He serviced my 55’s the other year. He might be able to advise how that piece should be fixed in.

    If it’s anything like the damping cartridge, the bits are easy to shear off

    Premier Icon DiscJockey
    Free Member

    Thanks again – very useful info….

    I’m also curious about the following: when I compress the forks up and down, there is a faint wheezing of air from under the ATA knob. Initially I suspected leakage out of the ATA cartridge, but after about 4 days and a couple of short rides, the pressure hasn’t dropped at all. One explanation I’ve had is that there must be air inside the stanchion itself, and presumably this gets pressurised when you push the fork down. Does this ‘extra’ pressure ever get factored in when setting up fork pressures, and is this air supposed to be allowed to escape, a question which is probably applicable to almost any fork out there…

    Premier Icon windydave13
    Free Member

    I’d say there shouldn’t be enough air in the fork leg to make a difference here. Mine went through a phase of leaking air into the leg, but of high enough pressure to start impeding travel.

    If they’re leaking through the top, I’d say you need to look at replacing seals 62 and 66 in the below. This is from the 2008 version but I assume there will be some similarities


    55_ATA_2008 by windydave13, on Flickr

    Premier Icon DiscJockey
    Free Member

    Thanks again for the diagram (where do you get these ?)

    Is item 59 a Presta valve core ?

    Premier Icon windydave13
    Free Member

    Yes. The last one if from the 08 ATA that has the PAR as well but I assume your’s may be made up similarly but without the extra air chamber.

    The diagrams are on this site: http://www.raceco-mtb.com/marzocchi/

    It’s a bit all over the place and sadly for 2009 they don’t seem to like to give a proper breakdown of what’s inside them, but still handy to have.

    Premier Icon DiscJockey
    Free Member

    Thanks for the link. Mine definitely has the 2009 ATA cartidge then:
    http://www.raceco-mtb.com/marzocchi/Docs/Gamme%202009/%E9clat%E9s%202009/MY2009%20-%2055%20ATA_R00-06.pdf
    which isn’t surprising as it’s the 2009 model !
    So no PAR. And as I want mine left at 160mm, I won’t worry too much about the broken height adjust spindle.
    I just found an old MBR from late 2008 – this model of fork was pretty damn expensive new, and I think the top model then, or next from top. I’ll just keep it well oiled – just bought a load of 7.5W from my local Ducati service centre – they’ve got it on tap !
    cheers !

    Premier Icon windydave13
    Free Member

    Good man. I use Rock Oil 7.5w in mine. I read somewhere that motorcycle fork oil can cause the seals to swell. Considering they have a tendancy to leak them swelling can only be a good thing!!

    I’ve looked at the new ones, but until they break properly there’s no point. Fingers crossed i get another trip to the Alps out of them 🙂

Viewing 27 posts - 1 through 27 (of 27 total)

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