A very quick note here on homologations etc...
YES there is a set of technical specifications defining how to build a motor. NO it's not really spec racing as this gives a set of parameters and each manufacturer builds whatever they think is best WITHIN these parameters.
Now, let's say we only had these rules and no homologation list....
You go to an event, strictly speaking EVERY motor there would need to be disassembled after EVERY run to make sure it's all within these specifications set.
So simply to avoid this, all the associations ask is the manufacturer/distributer to submit a sample to them before the season starts so they can check all is within the rules. If it is, it goes on the list, and you can use it at the events covered by those rules.
It's just a simple way of enforcing the rules laid out!
The reason there are different lists for different countries/blocks etc is because some products are not available or not supported in that region. This way it always gives the association a point of contact with that manufacturer.
Hope that clears things up a bit!