Yamaha TTR90(M) Owner's Service Manual page 116

AIR FILTER CLEANING
1. Install:
Air scoop right 1
2. Install:
Air filter case cover 1
3. Clean:
Air filter element
Clean them with solvent.
NOTE:
After cleaning, remove the remaining solvent
by squeezing the element.
CAUTION:
Do not twist the element when squeezing
the element.
Leaving too much of solvent in the ele-
ment may result in poor starting.
4. Inspect:
Air filter element
Damage
5. Apply:
Foam-air-filter oil or engine mixing oil
To the element.
NOTE:
Squeeze out the excess oil. Element should
be wet but not dripping.
6. Install:
Air filter element 1
NOTE:
Align the projection a on the air filter case with
the hole b in the air filter element.
7. Install:
Air filter case cover
8. Install:
Air scoop (right)
3 - 4
INSP
ADJ
Replace.