KZ2 is a kart racing class using 125 cc water-cooled two-stroke engines yielding about 52 hp (39 kW).
Z2 is the second fastest of the KZ karting racing categories, and technical regulations are similar to faster KZ1 except that in KZ2 the gearbox must be "hand-operated and exclusively mechanical without a servo system", as well as the use of medium tires.
[1] Both the engine and chassis must be approved by the CIK-FIA racing governing commission.
The KZ2 class is run in both national and continental championships and is popular in Europe and the USA.
The NKF Super 4 series continues as KZ UK with a minimum weight of 180 kg but has no championship status.