Reproduced from the official JAG website:
The Motor Sports Association have now approved the introduction of ROTAX MAX EVO Accessories for use from the 1st January 2017 for the Rotax Max Senior & Junior Classes.
It is acceptable to use Accessories from EVO & Pre-EVO together at the same time. However in the case of the Senior Engine if the new Ignition system is employed then it is obligatory to use the EVO electronically controlled Exhaust Valve in its entirety. As an example, if the competitor decided to use the New EVO ignition etc. he would be at liberty to use his original Pre-EVO Exhaust and or Carburettor.
Minimax will remain unchanged in all respects. This means that 2017 Minimax regulations will remain exactly as per the 2016 regulations with the only exception being the allowed use of the New EVO Exhaust system. The New Exhaust will not provide a performance advantage in the restricted Minimax Class but will allow competitors to upgrade to the new type as the old variety becomes obsolete.
TYRES. Contrary to recent rumour the tyres for all Rotax Classes will remain unchanged for 2017.
Rotax Junior & Minimax will remain on MOJO D1 Slick tyres.
Rotax Senior Max will remain on MOJO D2 Slick tyres.
All Rotax Classes with remain on MOJO W2 Rain tyres.