Re: Hole in clutch case?!
We've seen this before. The theory is that something was loose and flopping around inside the cover. There's very little space between the gear and the cover so even a small foreign object can cause that damage. Looking at your photo I don't see the set screw that keeps the flower nut from loosening. It might have been that screw. I'd check for corresponding marks on the gears.
Like Leadfarmer said, there's nothing there to leak out so it isn't a big concern except for dirt and dust to get in. You can patch it with an epoxy based compound such as Devcon Liquid Aluminum, or similiar product or just cover the hole with tape. It isn't a structural part and only keeps the clutch clean.
A new cover can be ordered from several of the vendors here if you're not into repairing yours.
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Last edited by 2door; 12-15-2011 at 07:59 PM.