Servicing the LC4 chassis swingarm suspension link

Discussion in 'Thumpers' started by creeper, May 17, 2005.

  1. bfalcao

    bfalcao Adventurer

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    I had a huge up/down freeplay in mine (check video below) and found it was from both the bottom shock bearing and the frame bearings. After I replaced these bearings there was no freeplay whatsoever!! Freeplay of such nature can only be due to shotted bearings in the shock, frame and linkage, so I would inspect them carefully.

  2. mangas

    mangas Adventurer

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    You can easily locate it by jamming your finger in all pivots. In one of them you'll feel the finger being squeezed.

    My upper shock bearing was rather loose in frame and and required tightening it close to stripping the copper nut to fixate it in frame and stop from moving about the bolt.
  3. rockaholic

    rockaholic Adventurer

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    Ahoy, mateys!

    I was going through my swingarm the other night. The buckets and seals on the rocker arm itself were worn and corroded, but oddly the bearings seem rather good. Packed with dirty grease, but smooth and intact. The sleeves are nice and shinny as well. So I'll try to lathe off the corrosion on the buckets with some fine sandpaper, put new seals and grease the needles freshly. Should work.

    Got quite lucky with the lower shock bearing, as it seems to be impossible to find replacement. Mine wasn't wobbly, but a bit gritty when spinning. I didn't want to try taking it out straight away after reading your experiences. So I sprayed heaps of WD40 and put a compressor gun through the zerk hole. Had to repeat this flush many times. The compressed air pushed all the dissolved shite out and now the bearing spins like new. I will put good fresh grease into the zerk hole and push it in with air.

    However, not so lucky with the needle bearings and dogbone shaft on the frame. Seized and corroded badly. Pushed the shaft out, but the seals and bearings are in there frozen. Tried driving out with a hammer, but no luck so far. Last night I applied loads of WD40 and left it. I will try to force them out with the threaded rod method tonight.

    I have a couple of questions though.
    1. Can I apply sufficient heat to the frame tube to aid the operation without burning off the paint? Is it resistant to temperature at all?
    2. Not only the bearings, but the seals are stuck in there. Should I try to threaded-rod-push everything out at once? It will be more difficult to overcome friction from four seized components all at once, but I guess there is no other way around that. Or is there?
    3. I'm thinking of installing a zerk there as well and read that some of you have done this. Did it work? Is it worth the hassle?

    Anyway, thanks for all the wisdom and may you never face seized bearings again! Cheers
  4. mangas

    mangas Adventurer

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    It seems the frame dog-bone bearings are most prone to deterioration. On my Adv it was the only pivot that actually needed servicing, so I installed zerk. Drill, tap, install, same spot as https://advrider.com/f/threads/serv...rm-suspension-link.79990/page-8#post-15697516 did. Works well. Zerk from KTM (same part nr. as prolink) just clears the center stand with cap on, so i'd be cautios of any longer or bigger 90degree zerks. Don't over-tighten the Zerk - the head shears off very easily. Had to extract my first attempt.

    Heating with paint stripper gun at 600C from 10..15cm didn't touch the paint. But i tried to keep the distance so that the surface didn't get much hotter than frame and tried to direct most air into the bearing hole using a narrow nozzle. The seals are barely pressed in. If the bearings are shot, i'd try to collapse the cage by wedging something under it in the middle of tube.
    rockaholic likes this.
  5. JimmieDK

    JimmieDK Been here awhile

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    Found this linkage in the garage, same geometry as the LC4 link but takes a 32mm OD bearing. Also lacks a few reinforcements found on the LC4 link and no grease zerk. Not sure what bike it's from but it may come from the two type 502 ('92-'97) SX125 I used to have. Similar linkage system. Or could it be from some early LC4?
    Anyhow, as the stock bearing have seen better days I pressed in a new spherical bearing in the oddball link and fitted it all. New top shock bearing and there's virtually zero play at the end of the swingarm.
    Will it hold up, as I assume less wall thickness equals a weaker part?
    [​IMG]
    [​IMG]
  6. taraba

    taraba Adventurer

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    Hello everyone,

    I am resurrecting 625 SXC that was laying in a shed for several years.
    As expected, all seals are shot.

    Most of the things went smooth, apart from dogbone bearings in the frame which were rusted as hell

    [​IMG]
    [​IMG]

    And also ruined the axle
    [​IMG]

    I had to hammer the hell out of those bearings to get them out of the frame, even after liberal application of heat and WD40

    [​IMG]
    [​IMG]

    On to the linkage
    I replaced only the seals for two "normal" bearings but i am not sure if the spherical bearing aka pro-link bearing is done for or is still ok.
    [​IMG]

    Question: How do i know if the pro-link bearing is still fine or is ready for garbage?
    It has, what i would classify as, expected range of motion for spherical bearing, and no up-down play that i can feel.
  7. Parx400

    Parx400 Long timer Supporter

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    Did you hammer them and the seals out one side ? What did you put on the end of the old shaft?
  8. taraba

    taraba Adventurer

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    No. Seals were remove first with a screwdriver and only bearings were hammered from one side (as per picture above).
    I used socket, i believe size 16mm, at the end of old shaft.
    timeOday likes this.
  9. clintnz

    clintnz Trans-Global Chook Chaser

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    If there is still grease in the spherical bearing it is probably ok. As that bearing is expensive, before buying another one I would re-assemble & check again for play as it will be easier to feel it in the bike. If you do need to change it, it is not difficult to unbolt the linkage again.

    Cheers
    Clint
  10. taraba

    taraba Adventurer

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    Thanks for the tip clintnz.
    That's what i did already. Assembled the bike and checked the play in the swingarm - almost no play at all.
    I expect that some play is normal (feels like it reaaaly minor)?

    There was lot of grease in there but i need to pump some more to replace the old stuff.
    Only problem is that my hand operated grease gun will not budge when connected to the nipple.
    Need to get stronger gun i guess.
  11. meat popsicle

    meat popsicle Ignostic

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    taraba, note Chris' tip from Page 1 (thread author):

    I've also reinstalled the bearing so the grease hole lines up straight with the zerk... this improves the chances of getting a little grease in the bearing with a gun.
  12. husqvarna

    husqvarna Been here awhile

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    Ok, I am on my second iteration of clean up etc after I detected some up and down play at the back wheel. Once the linkage was out, all fittings still nicely lubricated, the play seems to be between the bolts and the bearing sleeves. The bearings themselves seem fine.

    Is this normal?
  13. meat popsicle

    meat popsicle Ignostic

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    sorry I can't give you good feedback on the play question husky,

    but I do have a question of my own: while mounting up a different motor to my bike I neglected to install #14 while putting the swingarm thru the frame & engine. I'm half tempted to zip tie it to the frame as it looks like its there to hold the rear brake hydraulic line from flappin' about. But maybe the donut part keeps dirt & grime from getting in?

    [​IMG]
  14. taraba

    taraba Adventurer

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    I had lost that thing on my old LC4 and never had issues, but it should be easy to install as you don't have to pull the whole swingarm off.
    Just back out the No. 12 bolt a bit, slide it in and push the bolt back.
    meat popsicle likes this.
  15. wrk2surf

    wrk2surf on the gas or brakes

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    So just for posterity and info on this link the zerk greaseable Hinge Bearing Blasted #54203083050 is no longer available. It may be able to be sourced from a specialty supplier but Like many parts of our beloved 640-625-620s an alternative now has to be found.
  16. wrk2surf

    wrk2surf on the gas or brakes

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    My 93 600 has no hinge bearing its the same roller as the others and uses a pipe fitted spacer
  17. ghostridergary

    ghostridergary Adventurer

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    meat popsicle likes this.
  18. timeOday

    timeOday Long timer

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    I hate this thread, every time it bubbles up it just makes me feel guilty for not servicing those dozen or so bearings down there.
  19. twqqis

    twqqis Adventurer

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    No sir no!
    I've just opened up mine, the dog bone bearings (fiche#50) were seriously rusted. Everything else looked good to go.
    Remember that they have been designed with lateral play to prevent binding, which however means grease will get pushed out faster than the rest :(

    It really wasn't as big a deal I thought to get the rear end disassembled to get there ... :D
    timeOday likes this.
  20. Pomp92

    Pomp92 Adventurer

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    Jun 4, 2013
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    Just finished installing new dos bone bearings and seals, new axle, mounting a greaser on the frame tube and regrasing all the prolink and swing arm bearings. Shock is being serviced too. I have a used prolink leverage with the hinge bearing blasted. I'll try to rebuild it with standard roller bearings as written in the post linked from ghostridergary and keep it as spare. My 625 sxc has 27000 km and lots of offroad and abuse from previous owners.
    twqqis likes this.