Dajudge just had a thread looking for a secondary for a 95, per that thread 97 and up had a diferent spline on the jackshaft. Primarys are almost a one size fits all, just make sure the crank is same size/tapper. I have read guys using cat/poo/ski donts primarys on yamaha. I would narrow your search to 600 twins if you want to just put it on as set up should be close if not the same as what hes currently running.