True maintenance could be a big factor but with age some parts can be hard to find an expensive, don't get me wrong the old ones belong aswell but to intice new younger people to the sport they can relate to more late model Mx bikes, I've only been to events in qld so I don't no what other states are like, how many people would have old bikes like 426s or 400s or 600s sitting in sheds would make great sidecars and cheap with parts readily available, i just want to see the sport grow & I can't see it happening unless we start getting some more lightweights i no they might not be classed as vmx as such but I think it's a better way to introduce new people to the sport