So Bahnsy you are saying that a dutch twin shock ( cr480 for example) would be legal then?
Which is certainly not the case. And that is because common sense and fair play are to be factored in which seem to be left out of most discussions on the internet. Pushing a 2010 model up to scruitineering at an actual vmx meeting would see it being put back on the trailer. A cr480 modified to twin shock would be able to run where it belongs in pre 85.
Not knowing all the models, but there is a Husky(as late as 84) and a Monty that are later models allowed in.
I think the real reason its called evo instead of pre 80 or pre 81 or pre 82 is because the cut off of this era obviously wants to encompass all bikes with two shocks, be air cooled and have drum brakes. Discs, water cooling and single shocks were not at a single year, they were all over the place. For me the perfect name for the class. Pre 85 takes bikes with one or all of the later upgrades.
The way I see it, evo is only a problem in cyber space or if you don't want to follow the rules as they were written. Not saying that you are either Bahnsy.