2003 YAMAHA BIG BEAR PRO 400 maintenance

8-47
8. Reinstall the element to the element guide.
9. Reinstall the element assembly and parts re-
moved for access.NOTE:The air filter element should be cleaned every 20 ~
40 hours. It should be cleaned and lubricated 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 fittings for an air-tight
seal. Tighten all fittings securely to avoid the pos-
sibility 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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8-49
EBU00296
Carburetor adjustment
The carburetor is a vital part of the engine and re-
quires very sophisticated adjustment. Most adjust-
ing should be left to a Yamaha dealer who has the
professional knowledge and experience to do so.
However, the idling speed may be performed by
the owner as a part of the usual maintenance rou-
tine.CAUTION:
The carburetor was set at the Yamaha factory
after many tests. If the settings are disturbed
by someone without sufficient technical
knowledge, poor engine performance and
damage may result.
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8-61
EBU00820*
Brake fluid replacement
1. Complete fluid replacement should be done
only by trained Yamaha service personnel.
2. Have a Yamaha dealer replace the following
components during periodic maintenance or
when they are damaged or leaking.

Replace all rubber seals every two years.


Replace all hoses every four years.
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8-87
EBU00385
Battery maintenance
1. When the machine is not used for a month or
longer, remove the battery and store it in a
cool, dark place. Completely recharge the
battery before reinstallation.CAUTION:
A special battery charger (constant voltage/
ampere or constant voltage) is required for re-
charging a sealed-type battery. Using a con-
ventional battery charger may shorten the
battery life.2. Always make sure the connections are cor-
rect when putting the battery back in the ma-
chine.
EE.book Page 87 Monday, June 18, 2001 10:18 AM