check engine YAMAHA YFZ450 2005 User Guide

8-8 * Since these items require special tools, data and technical skills, have a Yamaha dealer perform the service.
Engine oil filter element
Replace.Drive chain
Check and adjust slack/alignment/clean/lube.Front brake*Check free play/operation/fluid leakage/
See NOTE Page 8-9.
Correct if necessary.Rear brake*Check operation/fluid leakage/See NOTE Page 8-9.
Correct if necessary.Clutch*Check operation.
Adjust if necessary.Wheels*Check balance/damage/runout.
Replace if necessary.Wheel bearings*Check bearing assemblies for looseness/damage.
Replace if damaged.Steering system*Check operation.
Repair if damaged.
Check toe-in.
Adjust if necessary.Front and rear
suspension*Check operation.
Correct if necessary.Upper and lower arm
pivot and steering shaft*Lubricate every 6 months with lithium-soap-based grease.Rear arm pivot*
Lubricate every 6 months with lithium-soap-based grease.Fittings and fasteners*Check all chassis fittings and fasteners.
Correct if necessary.Lights and switches*Check operation.
Adjust headlight beams.
ITEM ROUTINEWhichever
comes firstINITIAL EVERY
month136612
km
(mi)320
(200)1,200
(750)2,400
(1,500)2,400
(1,500)4,800
(3,000)
hours 20 75 150 150 300
U5TG61.book Page 8 Friday, April 2, 2004 11:28 AM

8-23
EBU13932
Engine oil and oil filter element
The engine oil level should be checked before
each ride. In addition, the oil must be changed and
the oil filter element replaced at the intervals spec-
ified in the periodic maintenance and lubrication
chart.
To check the engine oil level
1. Place the ATV on a level surface.
2. Start the engine, warm it up until the engine
oil has reached a normal temperature of
40°C, let it continue to idle for ten seconds or
more, and then turn the engine off.NOTE:_ To achieve the proper engine oil temperature for
an accurate oil level reading, the engine must
have first completely cooled down, and then
warmed up again for several minutes to normal
operating temperature. _
U5TG61.book Page 23 Friday, April 2, 2004 11:28 AM

8-25 1. Engine oil tank 2. Engine oil tank filler cap
3. Dipstick 4. Maximum level mark
5. Minimum level mark 6. Engine oil filler cap
1. Réservoir d’huile de moteur
2. Bouchon de remplissage de l’huile de moteur
3. Jauge
4. Repère de niveau maximum
5. Repère de niveau minimum
6. Bouchon de remplissage d’huile de moteur
1. Depósito de aceite de motor
2. Tapa de relleno del depósito de aceite de motor
3. Varilla de medición
4. Marca de nivel máximo
5. Marca de nivel mínimo
6. Tapa del filtro de aceite de motor
3. Remove the engine oil tank filler cap, wipe
the dipstick clean with a clean rag, insert it
back into the filler hole (without screwing it
in), and then remove it again to check the oil
level.NOTE:_ The engine oil should be between the minimum
and maximum level marks. _4. If the engine oil is below the minimum level
mark, add sufficient oil of the recommended
type through the engine oil tank filler hole to
raise it to the correct level.NOTE:_ When adding oil, be careful not to overfill the en-
gine oil tank; the oil level rises faster starting from
the half-level-portion on the dipstick. _5. Insert the dipstick into the engine oil tank filler
hole, and then tighten the engine oil tank filler
cap.
U5TG61.book Page 25 Friday, April 2, 2004 11:28 AM

8-29 1. Crankcase engine oil drain bolt
1. Boulon de vidange d’huile du carter
1. Perno de drenaje de aceite de motor del cárter
1. Engine oil tank drain bolt
1. Boulon de vidange du réservoir d’huile
1. Perno de drenaje del depósito aceite de motor
4. Remove the engine oil filler cap and the
crankcase engine oil drain bolt.
5. Remove the engine oil tank filler cap and the
engine oil tank drain bolt.
6. Check the washers for damage, and replace
if necessary.
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8-37
CAUTION:_

In order to prevent clutch slippage (since
the engine oil also lubricates the clutch),
do not mix any chemical additives. Do not
use oils with a diesel specification of “CD”
or oils of a higher quality than specified. In
addition, do not use oils labeled “ENERGY
CONSERVING II” or higher.


Make sure that no foreign material enters
the crankcase.
_14. Start the engine, and then let it idle for seve-
ral minutes while checking it for oil leakage. If
oil is leaking, immediately turn the engine off
and check for the cause.
15. Turn the engine off, and then check the oil
level and correct it if necessary.
16. Install the engine guard by installing the bolts,
and then tighten them to the specified torque.
U5TG61.book Page 37 Friday, April 2, 2004 11:28 AM

8-41 1. Maximum level mark 2. Minimum level mark
3. Coolant reservoir 4. Coolant reservoir cap
1. Repère de niveau maximum 2. Repère de niveau minimum
3. Vase d’expansion 4. Bouchon du vase d’expansion
1. Marca de nivel máximo 2. Marca de nivel mínimo
3. Depósito de refrigerante
4. Tapa del depósito de líquido refrigerante
EBU10151
Cooling system
1. Check the coolant level in the coolant reser-
voir when the engine is cold as the coolant
level will vary with engine temperature.NOTE:_ The coolant should be between the minimum and
maximum level marks. _2. If the coolant is at or below the minimum level
mark, remove the coolant reservoir cap, and
then add coolant or distilled water to raise it to
the specified level.CAUTION:_ Hard water or salt water is harmful to the en-
gine. You may use soft water if you can’t get
distilled water. _
Coolant reservoir capacity
(up to the maximum level mark):
0.29 L
U5TG61.book Page 41 Friday, April 2, 2004 11:28 AM

8-51
CAUTION:_ Hard water or salt water is harmful to the en-
gine. You may use soft water if you cannot get
distilled water. _12. Install the radiator cap and the coolant reser-
voir cap.
13. Start the engine and let it idle for several min-
utes. Stop the engine, and then check the
coolant level in the radiator. If it is low, add
more coolant until it reaches the top of the ra-
diator.
14. Check the coolant level in the reservoir. If it is
low, add coolant to the maximum level mark.
15. Start the engine and then check for coolant
leakage.NOTE:_ If any leakage is found, have a Yamaha dealer
check the cooling system. _16. Install the panel.
U5TG61.book Page 51 Friday, April 2, 2004 11:28 AM

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. _
U5TG61.book Page 71 Friday, April 2, 2004 11:28 AM

8-75
EBU13970
Idle speed adjustment
A special tester is needed to check the engine
r/min on this model.
Therefore, take the ATV to a Yamaha dealer to
have the idle speed adjusted.
EBU03030
Valve clearance adjustment
The correct valve clearance changes with use, re-
sulting in improper fuel/air supply or engine noise.
To prevent this, the valve clearance must be ad-
justed regularly. This adjustment however, should
be left to a professional Yamaha service techni-
cian. Specified idle speed:
1,750–1,850 r/min
U5TG61.book Page 75 Friday, April 2, 2004 11:28 AM

8-147
EBU07240Troubleshooting chart
Starting problems or poor engine performance1. Fuel
Check if there is fuel
in the fuel tank.There is fuel.Turn the fuel cock
lever to “OFF”.No fuel.Fuel cock is
clogged.
Clean the
fuel cock. Some fuel.Turn the fuel cock
lever to “RES”.Restart the engine.
No fuel.Supply fuel.
2. Compression
Use the electric
starter to see if
there is compression.There is compression.
Compression normal.
No compression.Ask a Yamaha dealer to
inspect.
3. Ignition
Remove the
spark plug and
check the electrodes.WetWipe clean with dry cloth.
DryAttach spark plug cap and
ground to chassis.Use the
electric starter.Spark is good.Ignition system is
normal.
Spark is weak.
Adjust the spark plug gap
or replace the spark plug. No spark.
Ask a Yamaha dealer to
inspect. 4. Battery
Use the electric starter.Engine turns over
quickly.Battery is good.
Engine turns over
slowly.Check the battery lead connections,
and charge the battery if necessary.Check the
fuel flow.
Turn the fuel cock
lever to “ON”.
Remove the fuel hose
from the fuel cock.
U5TG61.book Page 147 Friday, April 2, 2004 11:28 AM