LC4 Sprocket seal replacement...

Discussion in 'Thumpers' started by creeper, Oct 29, 2005.

  1. humdinger

    humdinger bp

    Joined:
    Feb 13, 2006
    Oddometer:
    616
    Location:
    South eastern coast , Australia
    BTW, I was :tb over that pic of your bike above. Sure was purdy; perhaps to purdy for the egos of the gods...[/quote]


    Yes, an impressive & well maintained piece of machinery. Was !?
    Sorry, hope you are healing well!!!
    #41
  2. creeper

    creeper Still alive...

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    Most output shafts I've seen have a little play designed into them to accomodate alignment... some more some less.
    To be honest, I don't know where the play comes from in an LC4. There is a roller bearing on the drive side and a needle bearing on the left side. One of these days I look to see if the play is the shaft moving in the bearing, play in the bearing or the bearing moving in the case.

    KTM lists the max axial transmission shaft play as 0.40mm (.016").
    I said last night about an 1/8" (.125") give or take was OK... which is grossly out of line with KTMs spec, I decided to measure mine this morning.
    My shaft axial endplay measures .013". I will correct my error in that other thread.

    [​IMG]

    _________________________________________________

    I have little dabs of yellow paint on the CS sprocket and nut as well as the nuts and carrier of the wheel sprocket... and the front caliper carrier, the brake pedal eccentric, the brake rod, starter bolts, banjo bolts, shifter bolt, oil filter and about a half dozen other places where I can take a 1 minute walk-around inspection. :wink:

    C
    #42
  3. b17flyguy

    b17flyguy Adventurer

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    Bay Area
    What kind of yellow paint do you use? :scratch
    #43
  4. creeper

    creeper Still alive...

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    Harley touch-up paint. :nod... :lol3
    #44
  5. meat popsicle

    meat popsicle Ignostic

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    It doesn't look like metalflake... :scratch

    Anyway, So how does that CS shaft attach inside the beast's belly? Wait, scratch that - I am going to look at my diagrams and see if I can figure it out.
    #45
  6. creeper

    creeper Still alive...

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    Wanker. :brow
    #46
  7. itsoKtoThuMp

    itsoKtoThuMp n00b

    Joined:
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    9
    Followed this today, worked a treat!

    Was a little bit of a pain getting the seal to stay square, really worth taking your time over!

    Also the seal puller was a great help. Would have been tricky with out it.

    I thought about self tappers and mole grips..?

    Anyway, thanks for the help :thumb
    #47
  8. Pole

    Pole Adventurer

    Joined:
    Oct 15, 2007
    Oddometer:
    30
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    PL
    Hi guys
    I have replaced the seal + o-ring + bushing last week but I've knocked the seal until it stopped against the bearing, it's below flush at the moment.
    Does it make any difference ( is there a gap needed between the back of the seal and the bearing ), should I pull it out and fit a new one but flush this time???
    Funny enough but this seal gave me a nightmare recently :cry
    #48
  9. creeper

    creeper Still alive...

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    These are the things that come to mind... bearing in mind that I've not had a LC4 in a few years now.

    The sprocket spacer will develop a second set (if it's a double lip seal) of wear patterns. This will probably be fine, if the spacer is in good condition and smooth across it's length.

    It shouldn't matter too much on depth, as long as the seal is square to the bore... the advantage of flushing it to the bore is that it's easier to tell if it's square.

    Installing the seal until it bottoms to the bearing can create problems in that you don't know if you've damaged the seal... did it just bottom, or did you give it a few taps after it bottomed? Assuming you didn't beat the living crap out of it, it should be fine also.

    All you can do is keep any eye on it... chances are it's all good, but if it leaks, then maybe next time go for the flush install. :wink:

    Cheers,
    C
    #49
  10. Pole

    Pole Adventurer

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    I have knocked it in gently, with barely any force.

    I did removed the seal and fitted a new one "your" way.
    This is how it's fitted by the factory I assume, because when I have removed the OEM one it was fitted a bit above flush.
    I was wondered why KTM didn't have knocked it right in, to the bearing.
    For this 32mm socket works ok.
    Next thing I will do is to lathe a fitting tool to do the job properly :wink:

    Right, 6000 miles: cylinder base gasket leak, front sprocket seal leak... what's next... :lol3
    #50
  11. DANNOj

    DANNOj Long timer

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    2,176
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    Perth, Australia
    Attention fellow LC4 owners... a little help please!

    I thought this was a good place to ask the question, save starting a new thread....

    My CS seal sprung a leak, so I replaced the seal, o-ring and bushing. For some reason it leaked again almost straight away (within the first 100km), so I replaced the seal and o-ring again.

    And... bugger me! It leaked AGAIN, within the first 100km, and quite profusely.

    Each time that I pull it apart, the o-ring has been munched.

    A close inspected after wiping everything clean confirms that the leak is coming from between the spline and the inside of the bushing, not from between the seal and the outer edge of the bushing.

    [​IMG]

    [​IMG]

    I am at a loss as to what to do. I pulled the bushing out just now, and, as usual, the o-ring is kind of broken, and in a couple of parts. But still a full ring, but in a couple of rings.

    When I install the o-ring and the bushing, I make sure I lube them up with a little oil.

    The sprocket nut is not coming loose.

    The o-ring is direct from KTM, red in colour, and is part# 0770250021.

    HELP!! What is causing it to leak?

    Any advice appreciated.
    Thanks,
    Dan
    :thumb
    #51
  12. JSracecars

    JSracecars Adventurer

    Joined:
    Feb 25, 2010
    Oddometer:
    45
    if you are running an aftermarket sprocket that isnt the right width then it won't press the sleeve onto the o ring tight. causing the sleeve to cut the o ring up.
    #52
  13. DANNOj

    DANNOj Long timer

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    Thanks for the idea JS -- although this sprocket has been on the bike various times before with no issue.... HOWEVER, that makes me think..... I do swap sprockets on and off a fair bit..... I wonder if the washer is worn and crushed to the point where it has reduced the thickness, and is not pressing on hard enough?

    Might pay to replace the washer and nut?

    Cheers,
    Dan
    #53
  14. WestOzKLX

    WestOzKLX Elsie with Allspeeds

    Joined:
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    Western Australia.
    Sorry to hear about your woes Dan.:huh

    Seems like a common problem on the 640. Another inmate had the same issue that caused him to bail early on a multi state ride.:cry

    I was interested so I took a look at the KLX as a comparison and it seems it has a 2 piece selector shaft. (No direct link from the gear selector to the selector forks.) The shaft is split in 2 pieces with the serviceable items (seal and needle roller bearing) on the outer part behind a secondary cover. The inner shaft connect to the selector et al.

    Did KTM drop the ball on this design or is it the KLX design that is odd and not commonplace among other dirt orientated designs from The Orient?


    Opinions!:deal
    #54
  15. Pipo Zaro

    Pipo Zaro Carpe Diem

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    Hi Creeper, you save my bike, Tks.

    Now, to ride the Atacama Desert.:evil
    #55
  16. ini88

    ini88 Been here awhile

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    New York, NY
    I am going to be doing this job this weekend. I will take some pics. One thing I noticed is that Munn Racing sent me a different outer seal. All black rubber, and looks like the newer style seal that you see on car axles.

    Here is a photo of the outer seal that I got. I will try to take some photos with the install
    [​IMG]
    #56
  17. ini88

    ini88 Been here awhile

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    I replaced the seal today and it was a lot easier than I anticipated. Took all of 30 minutes. I thought the new CS seal would be a pain in the ass but it knocked it nice and smooth.

    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]

    I didn't have a seal puller, so I used a flathead screw drive and a hammer and slip the seal in half and got it out that way. Be careful not to hit the case!
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]

    Put it back together and put the old 16 tooth sprocket back on while I was at it
    [​IMG]

    Old spacer and seal. Space didn't look too bad, seal had some splits in it.
    [​IMG]
    [​IMG]

    Hope this helps you guys out.
    #57
  18. tdreyer

    tdreyer KTiM

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    Used to live in Crestview FL, now ????
    Great photos! In the second pic it looks like the C/S nut may have loosened and taken the pressure off the O-ring? Maybe that is why she was leaking>
    #58
  19. makazica

    makazica Been here awhile

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    Zagreb, Croatia
    +1....often happens to me cause i change sprockets a lot....
    #59
  20. gunnerbuck

    gunnerbuck Island Hopper

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    The seal you used for a replacement is just a generic seal available at any bearing shop... The oem unit has the metal outer plate to make it a little more damage resistant...

    Looking at your seal bushing it is very likely that the shagged O-ring was causing the leakage and not the seal bushing relationship... A failed O-ring is what causes leakage at the countershaft in most cases...
    #60