This is my only post on this thread so the usual posters that rip me after just about every post need not bother on this occasion.
I think everyone realises that the difference between an '81 43mm Yamaha front end and an '82 is academic. The 43mm Honda front end from ’82 is also very similar and possibly academic.
Unfortunately the front forks are the thin edge of the wedge so to speak. What happens when someone shows up with a CR250 ’80 model with an ‘84 CR500 or '99 XR600 engine or an RM250T frame with an RM500 engine? A C&J Honda replica frame with a ’99 XR600 engine.
The engine has not been modified in any case maybe the frame has but that is perfectly OK under the proposed rules otherwise every one of those 4T specials or engine swap bikes out there are illegal.
Heaven VMX I agree with what you are saying.
Also please note despite what many think EVO does have a period.
Below is the current rule
14.2.15.3. Bikes will be OEM. Modifications converting later equipment to comply will not be allowed.
All components will be of the period the machine was manufactured.
a) No linkage suspension
b) No Disc brakes
c) Air cooled motors
so please note the wording
"All components will be of the period the machine was manufactured." so really the components for each bike should come from the year
that bike was manufactured. So the forks for a 1978 to 1980 CR should come off a bike from that year. Also a Husqvarna 500 is the only bike that should be able to run a flat slide carby off an RM465 83 or 84 model.
Clearly this is not totally workable. That wording should also mean that everything including motor parts (pistons & rings) controls etc should come from the period the bike was manufactured.
With regards using new shocks etc particularly for EVO any shocks you can buy new (now) are not radically different from what was available back in the day. For the older classes although not written anywhere you can not use externally adjustable shocks for Pre 78 and there are other restrictions for older classes.
The machines in all Classic/Vintage forms of Motorsport are now mechanically better than they were back when new.
There also needs to be a rule permitting replica parts. Right now there isn't one. One example is magnesium hubs and brake backing plates become fragile with time. You should be able to remake them and if needed improve them for safety. There are examples of this but I'm not going to open that up here. Any replica parts maybe should be submitted to MA of approval.
I have my own opinion as to why the rules are being changed now. I won't express it here.
Kevin