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Recurring failure of countershaft/clutch pushrod seals

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by Loz, Apr 20, 2009.

  1. I've replaced the seals in my transmission cover twice now, and after maybe 5-10,000km they seem to regularly fail again. One's a clutch pushrod seal, the other's the countershaft seal. I can't tell which is failing, all I know is that oil gets through into the area under the sprocket cover and the bugger ends up dripping oil, which shits me, because it's not even British.

    I wouldn't mind if they were easier seals to replace, but you've really got to cut the chain to get to them without munting a gasket.

    I'm gonna replace the f*ckers again soon - any ideas on how to stop it from happening again? Sand down the pushrod and the countershaft? Why do these things usually fail, and how long is it reasonable to expect them to last?

  2. Any oil seal that retains oil behind it and a rotating component like a countershaft will fail prematurely if the rotating part itself has any wear or damage where the seal makes contact. If the area around the seal is not kept clean, any oil or grease (excessive chain lube too) will attract grit to form a paste which wears the rotating part where the seal touches. If that's what's happened you'll be able to see and/or feel the groove. If there's a groove, any new seal will fail too.

    The other reason such a seal will fail is if the bearing supporting the rotating part is flogged. If there is any way for the axis of rotation to float or move about, the seal chops out very quickly. This can cause the problem above just to compound things.

    It's unlikely that the clutch pushrod is rusty if you have had a heap of leakage there, but rust will chafe up the seal in quick time.

    Here endeth the lesson on leakage.
  3. Roger that, I'll have a bloody good look when the time comes, and see if I can spot any bearing issues too.