K&N Replacement Air Filters. K&N air filters are ideal for extended use in dirty and dusty off-road riding and provide clean carburetion even at high altitude. As a rule, no jet changes are required with just a K&N filter element, however the spark plug condition should be checked for proper mixture after the first few miles of riding. If the airbox has been modified for increased air flow, the main jet size will need to be increased to provide the proper fuel mixture.Additonal Fitment:1981-1984 HONDA CR250R1981-1982 HONDA XR250R1981-1984 HONDA CR125R1982-1983 HONDA CR480R