Lateral play: LC4 Countershaft. How much is too much?

Discussion in 'Thumpers' started by Airhead, Sep 21, 2006.

  1. Airhead

    Airhead More human than human

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    OK...in attempting to track down a possibly real, possibly imaginary noise on my 2000 LC4E, I noticed that the countershaft has a bit of lateral play in it. The sprocket bolt is tight, and the sprocket is tight against the shaft...but if I grab the sprocket I can move the entire shaft in and out a small amount. Hard to tell exaclty how much, but enough that I can notice it. The shaft seal is not leaking...

    So, the question is, is this a problem? The bike has approximately 10,000 miles on it, much of that off-road. I've never really checked for play in the countershaft before, so I have no idea how long it's been like this, or if it is getting worse. And, if this is a problem, what's the fix?


    Thanks in advance!

    Jeff
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  2. creeper

    creeper Still alive...

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    KTM lists the axial or end play of both transmission shafts as .004" (0.10mm) to .016" (0.40mm).
    I've found it to be typically towards the high end of the range.

    It tends to seems substantial just moving it by hand, but if you put an dial indicator on it or use a caliper, it's usually in spec.

    C
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  3. Airhead

    Airhead More human than human

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    Thanks Creeper...I went out and measured it as best I could with calipers (not particularly accurate, since I have no way to clamp the calipers in place on the sprocket)...and I was surprised that what felt like a lot of play was really only somewhere around .5mm.

    All this was precipitated by the fact that I seem to be getting a new noise from the bike...hard to tell, though, with that engine and an Alu skid plate...:D I actually think that the noise is chain backlash...the chain is on the loser side of in-spec. I'm going to try to tighten up the chain a bit and see if the noise goes away...

    Thanks again for your help!

    Jeff
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  4. creeper

    creeper Still alive...

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    You know your LC4 engine is running fine by the about-to-explode noises it makes. If it ever gets really quiet.... run! :eek1

    Gearing changes can be good for some noise too. I run 15/40 and with the standard adjustment my chain rubs against the front inner chain guard screw. Klickity clack, klickity clack.
    If I went back to stock (or at least larger diameter) gearing it would go away.

    You could try lining your aluminum skid plate with some closed cell foam... might "absorb" some of the racket the plate radiates and seems to amplify.... that or take the damn thing off. :lol3
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  5. Airhead

    Airhead More human than human

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    No way...that racket gives me an advantage...no one wants to ride too close to me because it always sounds like my bike might fly apart at any moment...:lol3
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  6. creeper

    creeper Still alive...

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    That's called the "LC4 Advantage". The only people not scared of you are riding 1954 Panheads with loose pushrods and an open belt drive.
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