can anybody help

4 replies to this topic
  • wrk

Posted December 28, 2013 - 10:17 AM


i have recently purchased a WR 450 f 2006 off eBay and on getting it home and stripping it down to clean and re grease i have noticed the crankcase cover has been damaged by the drive chain,on a certain point on the crankcase there is something that looks like a hole with a small ball bearing in it that has been nicked by the chain and is weeping oil,can anyone tell me what this is? and its function? and the best way to repair it

many thanks


  • grayracer513

Posted December 28, 2013 - 02:17 PM


The transmission on the WRF is pressure oiled. The oil passage runs behind the cylinder from the right crankcase cover, then into the bore that the clutch release arm runs in. From there, it branches to each of the two shafts via the bearing pockets.

Pretty much whatever you have leaking that isn't coming from a seal in that area is going to be a broken crankcase, sold only in pairs. The repair is to TIG weld it. That can run into considerable expense if there's a lot of machine work to be done to restore the oil ways.

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  • KennyMc

Posted December 29, 2013 - 01:08 PM


Is this "hole with a ball bearing in it" something one could see on a bike with no damage?  How can you currently see the hole?  Any pictures?

  • wrk

Posted December 31, 2013 - 06:45 PM


Hi many thanks for replying yes it looks a standard thing but I dont know what it is or why it is there

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  • grayracer513

Posted January 02, 2014 - 01:13 PM


Exactly as I have mentioned.  That ball is factory inserted in the exposed end of the oil way that runs back from the clutch release arm bore to intersect a passage drilled up from the output shaft bearing.  The ball is leaking because the impact of the chain striking the case either put the hole out of round, or because the case was cracked into that drill way. 


In a very minor case of this kind, you can sometimes "stake" the aluminum back tighter around the ball, but only if you're lucky and only if there's no crack.  Try setting the ball slightly deeper first, then try going around the top of the ball socket with a center punch (prudently) to cinch it up.  If it works, don't play the lotto for a while.  Your luck will be used up.


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