thanks larry. im pretty certain that there was no washer there when i open it up, but ill have a good look around just in case.
As for the washer itself ive got one which is almost exactly the same size as the stock brass one, BUT its not brass-instead zinc. would this be alright to use instead of getting another stock one becasue unfortunately i dont have anybody with another basnhee, and i dont want to pay $25 AUS dollars to order another washer from the yamaha dealer.