maintenance YAMAHA YFZ450 2005 User Guide

8-71
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 air filter element maintenance is
performed, check the air inlet to the air filter case
for obstructions. Check the air intake duct between
the air filter case and the carburetor and the mani-
fold fittings for an airtight seal. Tighten all fittings
securely to avoid the possibility of unfiltered air en-
tering the engine. _CAUTION:_ Never operate the engine with the air filter ele-
ment removed. This will allow unfiltered air to
enter the engine, causing rapid engine wear
and possible engine damage. Additionally, op-
eration without the air filter element will affect
carburetor jetting with subsequent poor per-
formance and possible engine overheating. _
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8-73
EBU02960
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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8-87
EBU11860
Brake fluid replacement
Complete fluid replacement should be done only
by trained Yamaha service personnel. Have a
Yamaha dealer replace the following components
during periodic maintenance or when they are
damaged or leaking.

Replace the oil seals every two years.


Replace the brake hoses every four years.
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8-107 1. O-rings
1. Joints toriques
1. Juntas tóricas
EBU08050
Lubricating the drive chain
The drive chain must be cleaned and lubricated at
the intervals specified in the periodic maintenance
and lubrication chart, otherwise it will quickly wear
out, especially when riding in dusty or wet areas.
Service the drive chain as follows.CAUTION:_ The drive chain must be lubricated after wash-
ing the ATV or riding in the rain. _1. Clean the drive chain with kerosene and a
small soft brush.CAUTION:_ To prevent damaging the O-rings, do not clean
the drive chain with steam cleaners, high-pres-
sure washers or inappropriate solvents. _
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8-129 1. Negative battery lead 2. Positive battery lead
1. Câble négatif de batterie 2. Câble positif de batterie
1. Cable negativo de la batería 2. Cable positivo de la batería
EBU03850
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 volt-
age/ampere or constant voltage) is required for
recharging a sealed-type battery. Using a con-
ventional battery charger may shorten the bat-
tery life. _2. Always make sure the connections are cor-
rect when putting the battery back in the ma-
chine.
U5TG61.book Page 129 Friday, April 2, 2004 11:28 AM