Yamaha shows them as still available for the SH,SJ & SK. Part #4H7-25351-00-00.
But a better solution for you may be
http://www.myoldyamaha.com/product/341-25351-00-00 341253510000
They are in Calgary and show to have the 341-25351-00-00 in stock.
Everybody else(boats.net, NW Vintage, even Yamaha's Speed and Sport site) shows No Longer Available.
I'm not sure if there is a difference between the 2 parts other than the model prefix.