The series that I race is called ACR (American Classic Racing)www.acrmx.com
which was started by a couple guys that were not happy with AHRMA which is more about the machine being period correct than the actual racing. There are a lot of guys that were pro or almost pro in the 70's/80's that choose to race this series for a number of reasons, one being the level of competition and it still being gentleman racing, two is that we get to ride at the premier tracks in the east and are welcomed with open arms because there are no "mini" dads protesting every move that is made.
In the riders meeting at Central the president of ACR said that in there 13 years of existence there has never been a protest as a matter of fact. I for one am more likely to stop and pick up somebody that is down (I did at Evansville for someone who was stuck under there bike) than roost someone after block passing them in a corner and that is the mindset of most ACR riders. It is said in the riders meeting again and again that if you want a trophy just come up and get one and that is not worth getting hurt for a $6.00 trophy, we all have to work on Monday.
So, on to the mini class, there is an adult mini class that is supposed to be for ttr125's,drz's and the Honda CRF-fs which is what I ride. Some people do ride 85's and the CRF150 R both of which are real MX bikes not like the play bikes that we ride. In the helmet cam video you can see that group take off from the playbikes in no time at all because they actually have suspension and horsepower. There is the same mix of bikes in the ACR under 18 class with the same results but at ACR it is what it is and nobody complains.
I'm happy with my 150f and as long as your battling with a like bike it's all good. If I want to race a real bike I ride my YZ...