In the Netherlands, you can start your motorcycle career at 18, on a bike with an engine of max. 11kW AND max. 125cc capacity. So this excludes our youngsters to ride any WW2 bike like BSA, Norton or other 500cc motor.
This seemed to me a bit strange, the 11kW limit exceeds the 9kW of our M20, 16H and so on, the 500cc rule seemed superfluous, so I asked the RDW (that issues licenses) the WHY of this rule.
The reply I got was revealing in it simplicity: “Reduce to 125cc your engine capacity”.
So my question: is there anybody who has done this?
Needless to say, I intend to continue to pester them for a real answer. 
email (option): viaconsu [at] planet [dot] nl
The real answer is 'the laws an ass'...The same rule applies (more or less) in the UK...
Power to weight ratio figures, irrespective of cylinder capacity are the relevant factor...
A 13 BHP M20 weighing 450lbs has a lower power to weight ratio than a 12 BHP (the limit in Britain) Yamaha weighing 325 lbs
BSA .0288BHP/lb (34.6lbs per BHP)...
Yamaha .0369BHP/lb (27.08lbs per BHP....)
So, even at 500cc the BSA will be out accelerated by the Yamaha up to 60MPH on similar gearing....
It's unlikely most Eurocrats have grasped the essentials of this simple equation...After all, look at all the other dumb ass laws they have come up with....Ian
email (option): ian@wright52.plus.com
I agree Cas...I wouldn't propose removing limits..Only modifying them to make them more logical and to bring into the frame some larger, lower powered machines that would then become eligible for 'learner use'
My belief is a decent course early on followed by road miles on a low/moderate powered bike is the sensible option...
You really learn about handling, road surface conditions in various weathers etc. etc. by racking up the road miles...Ian
email (option): ian@wright52.plus.com