The lack of year model stuff is a huge source of the vagueness.
If a 1992 CZ 513 isn't very closely related to a 1984 CZ 513 (I'm sure they are, but if they aren't), then it has no more of a claim to being an Evo bike than a 2013 SexMax does.
If they are very closely related, then there's no problem in calling it a carry-over bike.
If we don't put an age restriction on Evo, then we can't stop nonsense like the SexMax.
Evo needs an age limit to turn it into a historic category.