Ths is funny to me...here in US AHRMA has I thought pretty specific class rules, and in fact I volunteer as a tech inspector. The biggest debate recently was the flat slide carby thing-now this applies to all Vintage and up. In Post Vintage, like the EVO classes you have we have thre area classes.
1. Historic most bikes 1975-1977( sounds like your pre-78 class, maybe that's where it came from as it looks like in Oz these classes have been run longer)
2. GP 1978-1981 about the same all twin shock except YZ
3. Ultima-allows Water cooled linkage bikes as long as no disc.
What is controversial is the only flat slide carbs allowed are mikuni Tms which were available in 1982-83-the Kehein(sp?) PJ,PWK etc are not allowed..oh yea Lectrons are alowed w/o powerjet in all Post Vintage classes.
Also controversial is the rule forbidding front drum conversions of bikes originally equipped with front disc. This of course, precludes all 82-up KXs, of which many would be otherwise legal....also 84 Cr.s due to this. Mostly, the one that hurts is the 83 KTM illegal since it came witha front Brembo disc...yet the 84 KTM( when they went back to a drum) is with USD WP forks( which were terrible anyway).
I have to say I would catch a modified 81 CR swingarm, or a converted KX, 84 CR etc, but I have probably let an 83 KTM by since it was so visually similar to the 82.
This past year twin leading shoe drums were banned from Historic class too. not a big deal to me. I have somehow been able to make a Maico brake work great-even with the stock short arm and all.
BTW since we define here for example GP up to 1981, the 43 mm forks are allowed.So, you can modify an earlier bike within the class to how it would have been possible up to 1981. The CR forks are also allowed since they are deemed the same as the YZ forks.
Still, that is not how it really was. Anyone who was racing 81, if they were racing a 79 bike-was only doing so due to lack of $. What I am saying is that at least I never saw anyone put later model production components on a two tear old bike then( and the cost then would have made the Simons seem cheap).
I think this is a delicate balance. We do not want to have so many ruls that it drives away new riders, or even suppliers. We need people reproducing parts, there is a finite supply.
Conversely, if we fail to enforce reasonable guidelines, we are not Vintage racing. There is some push here in the US for less and less rules. Many want now to have vintage classes for say 87-95 model bikes. I think this is because they are cheaper, and easier for some suppliers to get parts for....at our local club we have a decade class-puportedly for 10 yr old bikes. This of course changes every year, but on top of that they allow modern bikes in that class too, only not scored. Well, at some point more and more will get the modern bikes, since they really are cheaper, and cheaper to maintain(until you get to the 98 up four stroke era) and fewer and fewer race the old bikes. If some want to have vet classes on modern bikes, and this is really an untapped market-more power to them. ..but it is not vintage racing. At 39(40 in July), I have little interest in "my generation's" bikes, namely since there are few in my generation, and I raced this era(88-95), have no interest in re-living it-or roamcing a time when more and more were injured, seriously and fatally...yum.
We still have a great era from late 60s to early mid 80s that at least here in the US was the heyday of mx. I was too young, and parents couldn't afford to send me mxing. I now get to race the bikes I only watched as a child. Not only that, but my 7 yr old daughter loves the old bikes too. I ask you, how cool is that?
MJ
