Spark Arrester Cleaning - Yamaha BIG BEAR 4X4 Owner's Manual

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 performed, check the air inlet to the filter
case for obstructions. Check the air cleaner
rubber joint to the carburetor and manifold fit-
tings for an airtight seal. Tighten all fittings se-
curely to avoid the possibility of unfiltered air
entering the engine.
CAUTION:
Never operate the engine with the air filter
element removed. This will allow unfiltered
air to enter, causing rapid engine wear and
possible engine damage. Additionally, op-
eration without the filter element will affect
carburetor jetting with subsequent poor
performance and possible engine over-
heating.
EBU00754

Spark arrester cleaning

Select a well-ventilated area free of combusti-
ble materials and make sure the exhaust pipe
and muffler are cool.
1. Remove the purging bolt.
1. Purging bolt (× 1)
2. Start the engine and rev it up approxi-
mately twenty times while momentarily
creating exhaust system back pressure
by blocking the end of the muffler with a
shop towel.
3. Stop the engine and allow the exhaust
pipe to cool.
4. Install the purging bolt and tighten it.
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