New Spec Mini & Micro MAX for Grand Finals

The Micro and Mini MAX classes at this year’s Rotax MAX Challenge Grand Finals in Italy will use new MY20-spec engines.

Rotax has listed several benefits of the changes, including making the engine easier to use and install, plus less sensitive operation (ie, easier to tune both the carby and sprocket selection).

The MY20 (model year 2020) changes include a modified exhaust system plus an inlet insert that operates as a carburettor throttle body restrictor (makes the carburettor less sensitive to jetting changes).

BRP-Rotax press

BRP-Rotax is proud to announce that for the upcoming season in 2020, it will introduce several upgrades to both the Micro MAX and Mini MAX engine configuration, which will achieve four main objectives:

  • Ease of use & installation
  • Less sensitive operation
  • More cost effective
  • Limit manipulation of components.

These improvements further align the parity of the Rotax engine packages and ensure a more level playing field for our youngest RMC competitors.

The MY20 (model year 2020) configuration will already be introduced in the Micro MAX and Mini MAX classes at the RMC Grand Finals 2019 in Italy. The conditions for the Micro and Mini drivers remain just as equal as before, with this being the first time for all of them to use the race package.

Stefan Gruber, Manager Rotax Karting & OEM Business, RPS Business at BRP-Rotax firmly believes the upgrades are ensuring an even better, optimised engine package for the younger members of the Rotax family, “The improved Micro MAX and Mini MAX configurations have been extensively tested throughout the summer and the drivers’ feedback has always been the same: the packages are fun and easy to drive. From a mechanical point of view, it’s very easy to select the correct main jet and gear ratio. With this configuration, it will assist competitors to find their optimum settings without losing vital time and performance, plus it provides exceptional parity between engines. This will be a big benefit for the new starters to the sport and will give us even closer, exciting racing!”


The Rotax philosophy of creating a level playing field for competitors to enjoy close and fair racing, remains an important part of the direction the engine manufacturer takes when considering the best ways to provide this for their customers. Of course, not everyone is racing at such a young age, but the expectation of being able to begin karting without any basic know-how is undoubtedly a priority, in order to ensure the “fun” factor is not lost in a sport that can be more complicated than simple.

The 125 MAX engine range actually gives drivers the opportunity to progress from the baby of the class – Micro MAX through Mini, Junior and Senior using the same engine with relevant upgrades. The main advantage is naturally that the driver and mechanic understand the main fundamentals of Rotax. With standardised regulations around the world, the majority of Rotax MAX Challenge events allow competitors to participate with the Rotax products and accessories they are accustomed to.

The upgrades in detail:

The modified exhaust for both Micro MAX and Mini MAX is based on the original Micro package. An inlet insert (carburettor throttle body restrictor) makes the carburettor less sensitive to different settings in the jetting and gear ratios. This means choosing the correct main jet or sprocket, due to changes in conditions, is not as crucial and does not result in a big difference in performance between the various settings. It is also more effective with regards to the throttle response, which is especially helpful when the young driver or even their mechanic is less experienced.

The Mini MAX will use the same smaller radiator as the Micro MAX does already. To upgrade from Micro to Mini, you only have to change the exhaust socket and the internal parts of the exhaust, change the squish to Mini/Junior specification plus fit the new class-specific ECU, which is somewhat cheaper and alternatively simpler than the current upgrade process is now. These components make the installation of the Mini MAX engine package much easier on the same regulation 950mm chassis. This is another aspect that reduces the investment between the classes.

Rotax aims to minimise the cost for young drivers entering the sport with the smaller chassis and new upgraded configuration. Ultimately, reducing the weight of the overall kart and engine package in the Mini MAX category assists in increasing the safety aspect to a degree, that is, in many cases the initial introduction to racing for a lot of young drivers. The light weight and smaller package makes it consequently easier and more enjoyable for the newer driver as they continue to learn.

In addition, these upgrades will notably reduce the likelihood of the components (e.g. exhaust) being manipulated to improve performance outside the RMC regulations.

Compared to other cadet-age categories, the Rotax Micro MAX & Mini MAX offer reduced workload – service and maintenance – so cost of operation is therefore significantly lower. In general, this only means there can be more time spent on track having fun to the MAX!