Gasket help? And what is this??

[kristofrogers]

OK so i finally got the engine out of my trike after finally getting some time to work on it. I drained the oil and coolant and popped the left side case off. I drained the remaining fluid out and started to take a look at the rotor and interior. I took a razor blade to both contact sides for the gasket. Surprising enough the gasket came out in one piece but its very flimsy and brittle so i think it's a given that it needs replacing (which I'm going to be doing.) So I've always been told that before you replace a gasket you make sure both sides are clean and I've heard to add Vaseline to give it that stick factor. Is that basically it?

Also, on a different note, what the heck is this?? I noticed a little split in this cover on the side of the engine. When i pulled the cover off it was just filled with empty space.. like it was storage or something. The only thing inside was access to another bolt and a rubbery/plastic slide out...that's it. I'll post all the pictures below.



http://img.photobucket.com/albums/v302/shablaca/Photo05221814.jpg
The rotor seems a little pitted but nothing serious.

http://img.photobucket.com/albums/v302/shablaca/Photo05221815.jpg
Old gasket

http://img.photobucket.com/albums/v302/shablaca/Photo05221639edited.jpg
The hole in the cover

http://img.photobucket.com/albums/v302/shablaca/Photo05221638edited.jpg
Closer view

http://img.photobucket.com/albums/v302/shablaca/Photo05221807edited.jpg
....what is this circled area for...?

[pmktm]

If I remember right that was a dual sport motorcycle engine [non USA]. Thinking oil pump for auto lube. Not real sure tho.