1999-2004 Honda TRX400EX FourTrax Service Manual, Page 40Get this manual
MAINTENANCE Apply approximately 20 (0.7 oz) of Pro Honda Foam Filter Oil or equivalent oil from the inside of the elementPlace the element into plastic bag and spread the oil evenly by hand
PRO HONDA FILTER
Install the element core into the air cleaner element properlyInstall the element band onto the air cleaner element and the element assembly over the connecting tube flange in the housing securelyTighten the band screwInstall the air cleaner housing cover and secure it with the retaining clipsInstall the seathear fender assembly (page 2-2)