MOMS specifies only a maximum 4 year age spread in a single race. Therefore 12-16 y.o. fits best for our club
when a rider turns 16 y.o. they can continue for the remainder of that year as a junior. If they ride a senior race as a 16 y.o.they can not technically go back to juniors.
17 & 18 y.o. are absolutely senior.
The 250F 4T / 125cc 2T are not allowed to race against 85cc 2T / 150 4T. MOMS does not allow 250F in the same race as 85cc as capacity classes cannot be mixed. 85cc 2T and 150cc 4T are considered the same capacity class. 250F 4T and 125 2T moderns are considered the same capacity class.
Junior class at Heaven events is:
12-16years - 85cc 2T / 150cc 4T moderns (small wheel or big wheel no 65cc allowed as it is a different capacity class) or Pre85 125cc. now Pre85 125 in this context also includes Pre78, 75, EVO up to '84 etc etc as usual.
This is all as per the MOMS except for allowing 125 Pre85 which is the 'Heaven' way of encouraging VMX bikes in juniors. the 125cc Pre85 are about the same size / performace as a good modern 85cc 2T 150cc 4T particularly the big wheels.
The junior event is not critical to the HVMX program persay but is offered to allow our members to bring along their kids to make it a family weekend of riding. It is an important class to those families and the races are used to 'space' back to back races for us 'older' kids 
. I think everyone in the club supports their presence and several current senior riders have come through the Heaven junior class including current Heaven club champ and Pre78 125cc national champ Liam Beverly and 2013 No2 Carl Rindlisbacher.
Ted correct me if I'm wrong but a YZ80L would be completely legal at an 85cc modern race. One of the clubs juniors had his RM80 in the trailer last year at a modern meeting and his 85cc KTM had a very rare failure so he dragged the '78 RM80 out and rode it at the meeting and finished mid pack 
The YZ80L does not qualify as a Pre85 125cc due to the wheel size as per the MOMS but this does not matter for Heaven as there is only one junior class.
So just to clarify in simple terms the YZ80L is most welcome in Heaven junior races.
We have had this clarified again by a member of the MNSW MX Committee. MOMS only allows juniors to race bikes retailed as MX bikes on a man made track. Bikes such as TTR125, XR80/100 can race on natural terrain tracks. Gloucester is considered man made because it runs under a stadium cross track licence and has man made jumps even if they are only small to accomodate Pre65 etc. CRF150R is considered the same class as KTM SX85 and is sold as a junior MX machine.
We as a club try to encourage families to bring their juniors to Heaven meetings. The posts here seem to suggest that it is being made difficult when that could not be further from the truth. We try to come up with the best possible combination to allow the juniors to take part while still staying within the MOMS rules. If members feel we have misinterpretted a rule or can see a way to improve things then talk to a committee member. We welcome any suggestions as we are just guys that are trying to make the club run for everyones benifit. Other members, more often than not, have fantastic ideas that we need to know about for everyones benifit. Sometimes there is a very good reason that it cannot be done other times we go 'why didn't we see that' but all suggestions are explored.
This forum can not change anything in the Heaven Club the only way to do that is to bring it up to the committee or at a general meeting. Finally we are bound by the MOMS rules so often what looks to be an obvious solution may not be acceptable. A perfect example is juniors at Vinduros, that would be great, but the logistics of acheiving that is a nightmare.
Now can we get back to the approaching fun meeting at Gloucester 
We'll that makes 100 % sense.
Thanks for taking the time to write the post.
Funny my son can't wait to ride a "old bike"
I never thought he would.
Pretty cool I reckon "build em then race em" he might even learn something
Thanks again
