Yamaha BEAR TRACKER YFM250XR Owner's Manual page 288

9. Install the foam cover onto the air filter ele-
ment.
10. Install the air filter assembly and parts re-
moved for access.
NOTE:
The air filter element should be cleaned every 20–
40 hours. It should be cleaned more often if the
machine is operated in extremely dusty areas.
Each time filter element maintenance is per-
formed, check the air inlet to the filter case for ob-
structions. Check the air cleaner rubber joint to the
carburetor and manifold fittings for an airtight seal.
Tighten all fittings securely to avoid the possibility
of unfiltered air entering the engine.
CAUTION:
Never operate the engine with the air filter ele-
ment removed. This will allow unfiltered air to
enter, causing rapid engine wear and possible
engine damage. Additionally, operation with-
out the filter element will affect carburetor jet-
ting with subsequent poor performance and
possible engine overheating.
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