2004 Official factory service manual for Yamaha YFZ450S ATV Quad., Page 95Get this manual
CLEANING THE AIR FILTER ELEMENT 5Clean: air filter element
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
aWash the element gently, but thoroughly in solventWARNING
Use cleaning solvent which is designed to clean parts onlyNever use gasoline or low flash point solvents as they may cause fire or explosionbSqueeze the excess solvent out of the element and let it dryCAUTION:
Do not twist or wring out the elementThis could damage the foam materialcApply engine oil to the elementdSqueeze out the excess oilNOTE: The element should be wet but not dripping_