From 16 upwards.

Rotax Max
Uses a very powerful Rotax, 125cc TAG engine.  The maximum revs are limited electronically and are sealed to prevent unapproved tuning.  Care needs to be taken if starting in this class.  Weight limit for kart and driver is 162kg. Like many classes there is a higher weight variant called Rotax 177 for the heavier driver. Its weight limit for kart and driver is 177kg.

TKM Extreme
Uses a 115cc variant of the BT82.  As with the Juniors the chassis have to be registered, and new designs are only permitted every three years, to keep costs down. Weight limit for kart and driver is from 132kg. The class is not well supported at WSKC, but seems to be undergoing a revival further south.

Senior X30
The class is open to anyone 16 years and over, however, drivers may be allowed to compete in class in 16th year license permitting. The class is for the IAME X30 engine. It is a 2 stroke engine supplied with electric starter, 16,000 rev limit and centrifugal clutch. The class runs with a high grip tyre. Weight limit for kart and driver is 164kg with a driver minimum of 54kg.

Senior TKM 4 Stroke
This class uses the TKM K4S 4-stroke 200cc engine providing close and cost effective racing with high performance engines. Because of its quieter engine it is sometimes not considered as a competitive class. It is, however, a very economical formula that probably needs more skill to ensure smooth lines. It is a true “club” class that promotes good, keen competition. Weight limit for kart and driver is 162kg.

Senior Blue
Uses the water cooled, Parilla Lynx Reed Valve two stroke engine fitted with standard Tillotson carburettor. A restrictor is fitted in relation to the driver weight to adjust power output. The class runs with very sticky tyres.  Although still in existence this class has declined in popularity at WSKC. Weight limit for kart and driver is from 130kg

** Technical regulations are subject to change so please ensure you check the latest specifications. **