You must hold a current driving licence or a learner permit (from the 30th October 2007) before driving any motor vehicle in a public place. You can dr i ve only the type of vehicle for which you hold a licence/permit. And you must carry your driving licence/learner permit at all times when driving.
Motorcycles
Category A learner permit holders are entitled to d riv e motorcycles with:
an engine power output of 25kW or less, or
a power/weight ratio of 0.16kW/kg or less.
The restriction applies for as long as you hold a learner permit for this category and continues for the first two years of a full category A licence.
It is your responsibility to check the power of the motorcycle. If you are in any doubt, consult with the dealer/manufacturer.
Source: RSA