If the filter gets too dirty, it not let any air through. The engine overheats because it does not get enough air for cooling. By regularly changing you avoid expensive consequential damage. The motor protection filter eliminates unpleasant odors and protects your Kobold Motor.Thus, you that the filter keeps the optimum effect at all times and protects your engine. Suitable for: Kobold 135 Kobold 136 This filter should be changed every 6 months