Oil leaking between oil cover and crank case on 07' yz450?

2 replies to this topic
  • WAyz450rider

Posted July 02, 2015 - 05:12 PM


Hey guys,


I have an 07' yz450 where I am continually having an issue where oil keeps seeping out between the oil cover and crank case. It is seeping out at a pretty alarming rate. I have wasted about $30 already on oil and way to much time trying to see if I have fixed the leak. Here is what I have done so far:


1) Replaced all 4 o-ring gaskets which include the three small o-rings and the larger o-ring. I had noticed one of the three small ones was in pretty bad shape but just as a precaution replaced all of them. 

2) Ensured the o-rings are in in place (done this several times). For the small o-rings I put them on the bolts just after I put them through the cover to ensure they don't fall out. The third is definitely in the right spots when I put the cover on.

3) Tightened all 3 bolts down to spec.


There are no abrasions or cracks anywhere a long the case where the oil cover adheres to. I have done this numerous times in the past but noticed this problem just started popping up. The only conclusion I can come to is the oil cover may be warped. As this seemed to coincide with taking it to St. Anthony sand dunes where it was running super hot. 


Any ideas?


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  • WR250F

Posted July 02, 2015 - 09:33 PM


You can check to see if the cover is warped by putting the cover flat on a piece of glass and checking for gaps.

  • WAyz450rider

Posted July 10, 2015 - 10:34 PM


Ended up buying an after market Tusk oil cover for about $35 and seems to have fixed the issue. Hard to tell just by looking at my old one if it was dented or cracked but must have been as the new one has no leaks!

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