Honda HRS21 Owner's Manual page 31

Air Cleaner Service
A dirty air cleaner will restrict air flow to the carburetor. To prevent car-
buretor malfunction, service the air cleaner frequently.
1. Remove the wing nuts and the air cleaner cover.
Remove the element.
Carefully check the element for holes or tears and replace if damaged.
2. Tap the element lightly several times on a hard surface to remove excess
dirt, or blow compressed air through the filter from the inside out.
Never try to brush the dirt off; brushing will force dirt into the fibers.
If the element is excessively dirty, replace it.
WING
NUTS
ELEMENT
AiR CLEANER
COVER
29