FSC, as far as I know, the 'rules' for the Classics class (or 'Old School' as it will be in 2008) are not set by the club as such. They allow there to be a classic class, and it's up to the riders to decide how it should work. For 2007 it was a Pre 85 class. As I understand it, Twistandshout pushed for this class to be opened up beyond Pre 85 largely because he has an 86 CR Honda, but it also made sense to widen the criteria to try to get a few more riders, given how it's usually only a 6 or 7 bike field. But he was more aiming at a +20 years rule. However, that opens the gates to bikes with disk rears and USD forks. Apparently, the general feeling amongst the class regulars is that permitting bikes like that is just too close to moderns and really defeats the whole point of a classic class.
So where does that leave us?
Your 87 and 89 CRs wouldn't have been in with a show this year anyway, as it was Pre 85. You almost made it in with the new rules, but don't. I guess that's life, after all it's a bit hard to keep chopping and changing to suit every possible combination. What about the bloke with a 91 KX250 who reckons he has an old bike and should be able to ride?
I can't really say too much as I am not part of the committee nor do I have any part in setting the rules. For myself I couldn't care less, Pre 90 is nice and easy and I'd be happy to have it that way. But what we have is what we have, so I guess that's how it will be...