2010 YAMAHA GRIZZLY 125 engine

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RIDING DOWNHILL
WARNING

EWB01131
Going down a hill improperly could cause
overturns or loss of control. Always follow
proper procedures for going down hills as de-
scribed in this Owner’s Manual.

Always check the terrain carefully before
you start down any hill.

Never operate the ATV on hills too steep for
the ATV or for your abilities. The ATV can
overturn more easily on extremely steep hills
than on level surfaces or small hills.

Shift your weight backward and to the upside of the hill.

Never go down a hill at high speed.

Avoid going down a hill at an angle that
would cause the ATV to lean sharply to one
side. Go straight down the hill where possi-
ble.

Improper braking can cause the wheels on
the uphill side to come off the ground or
cause loss of traction. Gradually apply only
the rear brake when going downhill.
When riding your ATV downhill, shift your weight
as far to the rear and uphill side of the ATV as pos-
sible. Move back on the seat and sit with your arms
straight. Engine compression will do most of the
braking for you.
Use caution while descending a hill with loose or
slippery surfaces. Braking ability and traction may
be adversely affected by these surfaces. Improper
braking may also cause a loss of traction. Gradu-
ally apply only the rear brake.
Whenever possible, ride your ATV straight down-
hill. Avoid sharp angles which could allow the ATV
to tip or roll over. Carefully choose your path and
ride no faster than you will be able to react to ob-
stacles which may appear.

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EBU28783
PERIODIC MAINTENANCE AND ADJUSTMENT
EBU21671
Periodic inspection, adjustment, and lubrication
will keep your vehicle in the safest and most effi-
cient condition possible. Safety is an obligation of
the vehicle owner/operator. The most important
points of vehicle inspection, adjustment, and lubri-
cation are explained on the following pages.
WARNING

EWB01841
Failure to properly maintain the vehicle or per-
forming maintenance activities incorrectly may
increase your risk of injury or death during ser-
vice or while using the vehicle. If you are not fa-
miliar with vehicle service, have a Yamaha
dealer perform the service.
WARNING

EWB02561
Turn off the engine when performing mainte-
nance unless otherwise specified.

A running engine has moving parts that can
catch on body parts or clothing and electri-
cal parts that can cause shocks or fires.

Running the engine while servicing can lead
to eye injury, burns, fire, or carbon monoxide
poisoning - possibly leading to death. See
page 2-1 for more information about carbon
monoxide.
The intervals given in the periodic maintenance
and lubrication chart should be considered as a
general guide under normal riding conditions.
However, DEPENDING ON THE WEATHER,
TERRAIN, GEOGRAPHICAL LOCATION, AND
INDIVIDUAL USE, THE MAINTENANCE INTER-
VALS MAY NEED TO BE SHORTENED.
EBU27111
Owner’s manual and tool kit
Be sure to put this owner’s manual in the plastic
bag and to always carry it as well as the owner’s
tool kit and the low-pressure tire gauge in their re-
spective compartments under the seat.

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EBU21743
Periodic maintenance chart for the emission control system
TIP


For ATVs not equipped with an odometer or an hour meter, follow the month maintenance intervals.

For ATVs equipped with an odometer or an hour meter, follow the km (mi) or hours maintenance inter-
vals. However, keep in mind that if the ATV isn’t used for a long period of time, the month maintenance
intervals should be followed.

Items marked with an asterisk should be performed by a Yamaha dealer as they require special tools,
data and technical skills.
NO. ITEMCHECK OR MAINTENANCE
JOBINITIAL EVERY
Whichev-
er comes
firstmonth 1 3 6 6 12
km
(mi)320
(200)1300
(800)2500
(1600)2500
(1600)5000
(3200)
hours 20 80 160 160 3201
*
Fuel line


Check fuel hoses for cracks or other damage, and
replace if necessary.
√√√
2 Spark plug

Check condition and clean, regap, or replace if
necessary.
√√√√√
3
*
Valves


Check valve clearance and adjust if necessary.
√ √√√
4
*
Carburetor


Check starter (choke) operation and correct if nec-
essary.

Check engine idling speed and adjust if neces-
sary.
√√√√
5
*
Crankcase breather
system


Check breather hose for cracks or other damage,
and replace if necessary.
√√√

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EBU21864
General maintenance and lubrication chart
NO. ITEMCHECK OR MAINTENANCE
JOBINITIAL EVERY
Whichev-
er comes
firstmonth 1 3 6 6 12
km
(mi)320
(200)1300
(800)2500
(1600)2500
(1600)5000
(3200)
hours 20 80 160 160 3201Engine and V-belt
case air filter ele-
ment


Clean and replace if necessary.Every 20–40 hours (more often in wet or
dusty areas)
2
*
Front brake

Check operation and correct if necessary.

Check brake lever free play and adjust if neces-
sary.
√√√√√

Replace brake shoes. Whenever worn to the limit
3
*
Rear brake

Check operation and correct if necessary.

Check brake lever free play and adjust if neces-
sary.
√√√√√

Replace brake shoes. Whenever worn to the limit
4
*
Wheels

Check runout and for damage, and replace if nec-
essary.
√ √√√
5
*
Tires


Check tread depth and for damage, and replace if
necessary.

Check air pressure and balance, and correct if
necessary.
√ √√√
6
*
Wheel hub bearings


Check for looseness or damage, and replace if
necessary.
√ √√√
7
*
Upper and lower
arm pivots


Lubricate with lithium-soap-based grease.
√√√

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8 Drive chain

Check chain slack and adjust if necessary.

Check rear wheel alignment and correct if neces-
sary.

Clean and lubricate.
√√√√√
9
*
V-belt


Check for wear, cracks or other damage, and
replace if necessary.
√√
10
*
Chassis fasteners


Make sure that all nuts, bolts, and screws are
properly tightened.
√√√√√
11
*
Shock absorber
assemblies


Check operation and correct if necessary.

Check for oil leakage and replace if necessary.
√√√
12
*
Front knuckle piv-
ots


Lubricate with lithium-soap-based grease.
√√√
13
*
Steering shaft


Lubricate with lithium-soap-based grease.
√√√
14
*
Steering system


Check operation and repair or replace if damaged.

Check toe-in and adjust if necessary.
√√√√√
15 Engine oil

Change.

Check ATV for oil leakage, and correct if neces-
sary.
√ √√√
16 Engine oil strainer

Clean.
√√√
17 Transmission oil


Change.

Check ATV for oil leakage, and correct if neces-
sary.
√√
18
*
Moving parts and
cables


Lubricate.
√√√√
NO. ITEMCHECK OR MAINTENANCE
JOBINITIAL EVERY
Whichev-
er comes
firstmonth136612
km
(mi)320
(200)1300
(800)2500
(1600)2500
(1600)5000
(3200)
hours 20 80 160 160 320

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EBU23211
Checking 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 thespark 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).TIP

If the spark plug shows a distinctly different color,
the engine could be operating improperly. Do not
attempt to diagnose such problems yourself. In-
stead, have a Yamaha dealer check the ATV.
1. Spark plug cap
1

1. Spark plug wrench
1

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2. Check the spark plug for electrode erosion
and excessive carbon or other deposits, and
replace it if necessary.
To install the spark plug
1. Measure the spark plug gap with a wire thick-
ness gauge and, if necessary, adjust the gap
to specification.2. Clean the surface of the spark plug gasket
and its mating surface, and then wipe off any
grime from the spark plug threads.
3. Install the spark plug with the spark plug
wrench, and then tighten it to the specified
torque.TIP

If a torque wrench is not available when installing
a 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.
4. Install the spark plug cap.
EBU23266
Engine oil
The engine oil level should be checked before
each ride. In addition, the oil must be changed at
the intervals specified in the periodic maintenance
and lubrication chart. Specified spark plug:
NGK/CR7HSA
Spark plug gap:
0.6–0.7 mm (0.024–0.028 in)
1. Spark plug gap
Tightening torque:
Spark plug:
12.5 Nm (1.3 m·kgf, 9.0 ft·lbf)

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To check the engine oil level
1. Place the ATV on a level surface.
2. Check the engine oil level on a cold engine.
TIP

If the engine was started before checking the oil
level, be sure to warm up the engine sufficiently,
and then wait at least ten minutes until the oil set-
tles for an accurate reading.
3. Remove the engine oil filler cap, and then
wipe the engine oil dipstick off with a clean
rag.4. Insert the dipstick into the filler hole (without
screwing it in), and then remove it again to
check the oil level.TIP

The engine oil should be between the minimum
and maximum level marks.
5. If the engine oil is at or below the minimum
level mark, add sufficient oil of the recom-
mended type to raise it to the correct level.
NOTICE:
Be sure the engine oil is at the
correct level, otherwise engine damage
1. Engine oil tank filler cap
2. Dipstick
2
1

1. Maximum level mark
2. Minimum level mark
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