Air filter engine airfilter K&N 33-2966 The K&N air filters are simply exchanged for the standard air filters. No changes to the system are necessary. The standard setting on the carburetor does not need to be changed. By using K&N air filters there is no loss of performance, on the contrary because the potential of the air filter box is optimized. K&N air filters have the same service life as the engines. The unique filter system can extend the service life of the engines and provides optimal protection against hazardous dust, sand, etc. K&N filters are fully washable permanent filters that can be used over and over again with little maintenance.