Glad to hear you are doing well on the mighty KX500. I have a 1994 KX500 that I race motocross every weekend here in western NY. I race Senior B, +25B, Open Am, or the Vintage (5 years and older) classes. I never feel I am at a disadvantage being on an older bike. It is kinda nice going down to the line KNOWING that I will get the holeshot...
I have a 2001 Yamaha 426 (for sale), but I like the 500 better! My 250/450 friends think I am crazy though...
--Ben