Yamaha DT501988 Owner's Manual page 60

3. Remove the element from its case, and
clean it with solvent.
1. Air filter element
4. Apply recommended oil to the entire
surface of the filter and squeeze out the
excess oil. The element should be wet
but not dripping.
Recommended oil:
Yamalube 2-cycle oil or
air-cooled 2-stroke engine oil
7-12
®
5. When installing the element in its case,
be sure its sealing surface matches the
sealing surface of the case sothere is
no air leak.
6. The element should be cleaned at the
specified intervals. It should be cleaned
more often if tl;te motorcycle is operated
in dusty or wet areas.