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:2004-2008 YAMAHA TTR90E2000-2004 YAMAHA TTR90