2011 YAMAHA GRIZZLY 550 maintenance

8-22
8
EBU23213Checking the spark plug The spark plug is an important engine component,
which is easy to check. Since heat and deposits
will cause any spark plug to slowly erode, the spark
plug should be removed and checked in accor-
dance with the periodic maintenance and lubrica-
tion chart. In addition, the condition of the spark
plug can reveal the condition of the engine.
To remove the spark plug
1. Remove the spark plug cap.2. Remove the spark plug as shown, with the
spark plug wrench included in the owner’s tool
kit.
To check the spark plug
1. Check that the porcelain insulator around the
center electrode of the spark plug is a medi-
um-to-light tan (the ideal color when the ATV
is ridden normally).1. Spark plug cap1
1. Spark plug wrench
U28P62E0.book Page 22 Thursday, March 11, 2010 3:25 PM

8-24
8
TIPIf a torque wrench is not available when installing
the spark plug, a good estimate of the correct
torque is 1/4–1/2 turn past finger tight. However,
the spark plug should be tightened to the specified
torque as soon as possible.3. Install the spark plug cap.EBU27466Engine oil and oil filter cartridge The engine oil level should be checked before
each ride. In addition, the oil must be changed and
the oil filter cartridge 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. Check the engine oil level on a cold engine.
TIPIf the engine was started before checking the oil
level, be sure to warm up the engine sufficiently,
and then wait at least 10 minutes until the oil settles
for an accurate reading.3. Remove panel F. (See page 8-10.)
4. Remove the engine oil dipstick, and then wipe
it off with a clean rag.
5. Insert the dipstick completely into the oil filler
hole, and then remove it again to check the oil
level. Tightening torque:
Spark plug:
13 Nm (1.3 m·kgf, 9.4 ft·lbf)1. Engine oil dipstick
U28P62E0.book Page 24 Thursday, March 11, 2010 3:25 PM

8-28
8

Make sure that no foreign material enters the
crankcase.12. Start the engine, and then let it idle for several
minutes while checking it for oil leakage. If oil
is leaking, immediately turn the engine off and
check for the cause.
13. Turn the engine off, wait at least ten minutes,
and then check the oil level and correct it if
necessary.
14. Install panel F.EBU27306Final gear oil The final gear case must be checked for oil leak-
age before each ride. If any leakage is found, have
a Yamaha dealer check and repair the ATV. In ad-
dition, the final gear oil level must be checked and
the oil changed as follows at the intervals specified
in the periodic maintenance and lubrication chart.
To check the final gear oil level
1. Place the ATV on a level surface.
2. Remove the final gear oil level check bolt and
its gasket, and then check the oil level in the
final gear case. The oil level should be at the
brim of the check hole.3. If the oil is below the brim of the check hole,
remove the final gear oil filler bolt and its gas-
ket, and then add sufficient oil of the recom-
mended type to raise it to the correct level.
1. Final gear oil
2. Gasket
3. Final gear oil level check bolt
4. Correct oil level
1
243
U28P62E0.book Page 28 Thursday, March 11, 2010 3:25 PM

8-30
85. Refill with the recommended final gear oil to
the brim of the check hole as shown. NOTICE:
Be sure no foreign material enters the final
gear case.
[ECB00421]
6. Check the oil level check bolt gasket and the
oil filler bolt gasket for damage, and replace
them if necessary.
7. Install the oil level check bolt, the oil filler bolt
and their gasket, and then tighten the bolts to
the specified torques.
8. Check the final gear case for oil leakage. If oil
is leaking, check for the cause.EBU23426Differential gear oil The differential gear case must be checked for oil
leakage before each ride. If any leakage is found,
have a Yamaha dealer check and repair the ATV.
In addition, the differential gear oil level must be
checked and the oil changed as follows at the in-
tervals specified in the periodic maintenance and
lubrication chart. Tightening torque:
Final gear oil drain bolt:
23 Nm (2.3 m·kgf, 17 ft·lbf)
1. Final gear oil
2. Gasket
3. Final gear oil level check bolt
4. Correct oil levelRecommended final gear oil:
See page 10-1.
1
243
Tightening torques:
Final gear oil level check bolt:
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Final gear oil filler bolt:
23 Nm (2.3 m·kgf, 17 ft·lbf)
U28P62E0.book Page 30 Thursday, March 11, 2010 3:25 PM

8-33
8 8. Check the differential gear case for oil leak-
age. If oil is leaking, check for the cause.
EBU23470Coolant The coolant level should be checked before each
ride. In addition, the coolant must be changed at
the intervals specified in the periodic maintenance
and lubrication chart.EBU27125To check the coolant level
1. Place the ATV on a level surface.TIPThe coolant level must be checked on a cold en-
gine since the level varies with engine tempera-
ture.2. Check the coolant level in the coolant reser-
voir.TIPThe coolant should be between the minimum and
maximum level marks.
3. If the coolant is at or below the minimum level
mark, remove panel D to access the coolant
reservoir. (See page 8-10.)
4. Remove the coolant reservoir cap, add cool-
ant or distilled water to the maximum level
mark, install the reservoir cap, and then install
the panel. NOTICE: If coolant is not avail-
able, use distilled water or soft tap water
instead. Do not use hard water or salt wa-
ter since they are harmful to the engine. If
water has been used instead of coolant, re-
place it with coolant as soon as possible,
otherwise the cooling system will not be1. Maximum level mark
2. Minimum level mark
U28P62E0.book Page 33 Thursday, March 11, 2010 3:25 PM

8-38
818. When coolant begins to flow out of the bolt
hole, tighten the cylinder head air bleed bolt to
the specified torque.
19. Start the engine and let it idle for ten minutes.
20. Rev the engine five times.
21. Pour the recommended coolant into the radia-
tor until it is full.22. Stop the engine and allow it to cool. If the cool-
ant level has dropped after the engine has
cooled, add sufficient coolant until it reaches
the top of the radiator, and then install the ra-
diator cap.
23. Start the engine, and then check for coolant
leakage.
TIPIf any leakage is found, have a Yamaha dealer
check the cooling system.24. Install the V-belt cooling duct, and then tighten
the clamp screw.
25. Install the panels.EBU27805Cleaning the air filter element The air filter element should be cleaned at the in-
tervals specified in the periodic maintenance and
lubrication chart. Clean or, if necessary, replace
the air filter element more frequently if you are
riding in unusually wet or dusty areas.TIPThere are two check hoses at the bottom of the air
filter case, which are located behind panels D and
E. (See page 8-10 for an explanation on removing
1. Cylinder head air bleed boltTightening torque:
Cylinder head air bleed bolt:
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
U28P62E0.book Page 38 Thursday, March 11, 2010 3:25 PM

8-42
813. Install the panel.
TIPThe air filter element should be cleaned every 20–
40 hours. It should be cleaned and lubricated more
often if the ATV is operated in extremely dusty ar-
eas. Each time the air filter element maintenance
is performed, check the air inlet of the air filter case
for obstructions. Check the air filter case rubber
joint to the throttle body and the rubber joint mani-
fold fittings for an air-tight seal. Tighten all fittings
securely to avoid the possibility of unfiltered air en-
tering the engine.
EBU27812Cleaning the spark arrester Select a well-ventilated area free of combustible
materials and make sure the exhaust and muffler
are cool.
1. Remove the bolts.
2. Remove the tailpipe by pulling it out of the
muffler, and then remove the gasket.
3. Tap the tailpipe lightly, and then use a wire
brush to remove any carbon deposits from the
spark arrester portion of the tailpipe and inside
of the tailpipe housing.
1. Hose
1
1. Bolt
U28P62E0.book Page 42 Thursday, March 11, 2010 3:25 PM

8-44
8
WARNING
EWB02380Never run the engine in an enclosed area when
purging the spark arrester, otherwise it could
cause injury to the eyes, burns, carbon monox-
ide poisoning, possibly leading to death, and
start a fire.
Always let the exhaust system cool prior to
touching exhaust components.
Always wear eye protection, and make sure
no one is behind the ATV.
Make sure there are no combustible materi-
als in the area.EBU23930V-belt case drain plug After riding in water deep enough to allow it to en-
ter the V-belt case, remove this plug to drain the
water from the case.
TIPIf water drains from the V-belt case after removing
the plug, have a Yamaha dealer check the ATV as
the water may affect other engine parts.EBU29700Adjusting the throttle cable free play The throttle cable free play should be checked
and, if necessary, adjusted at the intervals speci-
fied in the periodic maintenance and lubrication
chart. Tightening torque:
Purging bolt:
27 Nm (2.7 m·kgf, 20 ft·lbf)1. V-belt case drain plug
U28P62E0.book Page 44 Thursday, March 11, 2010 3:25 PM