Well, I've been away from the computer just a day, and this almost passed by completely!
I like the 83 cutoff even though the stuff I really like became popular just after. One of the things I really like about this list is the flexibility most folks have about whats off topic. Some of my stuff I've needed information on, and have neither been let down, nor been taken to task for being a couple years off through lack of knowledge. I also like how some stuff thats not typical for it's era is accepted (like Alan, Vitus, etc).
Maybe we could just figure on bikes that have a certain "feel" to them regardless of age. Sort of the keepers of the flame thing, but alowing for models that were made for a few years after 83? I know that's vague, but its been a long day, and sometimes I'm just not great with words. To twist a common quote(dont remember by who though) I can't explain classic, but I know it when I see it.