I misplaced a Oil oring that is inside the left crankcase cover and was wondering if i should get one from the dealer seperate or buy THIS and if i buy this does it come with the oring i need?
I dont want to wait 2 months (thanks troy of yamaha) for little parts like that.

 

I would simply go to my local hardware store and buy a new O-Ring.
Thats what I did when I needed to replace an O-Ring.