I just bought a second hand seat for a 93 model for less than £10 of fleabay, keep an eye out for others, I did find some went for much morebut mine had a yellow overspray which stopped more bids, a quick wipe with thinners soon brought it back to black.
No idea what fits what but yamaha bits are often easy to swap over with little modifications. Have you tried a friendly yamaha dealers who may if asked nicely check parts numbers to cross reference bits.
beeman
