PW, 50 expert (ktm), 65, 85, youth beginner (65s & 85s getting feet wet), girls (13 & under), adult beginner (14+ big bikes first year racers), 125, 250, open, vet 25+, vet 40+, Women (14+). 12 minutes plus 1 lap.
There. Problem solved. Everyone go home (or offroad racing for real classes).