A few people,(myself included) think the earlier model has superior porting.My 86 is a nasty, nasty animal and loses nothing when up against my mates 93. Both are standard at minute bar pipes and ignition timing adjustment. And I run one tooth less on back sprocket.Ultimately, there aint a lot, if anything in it.As long as you look after it on a religious basis, it'll tear your shoulders out no matter what.