2015 YAMAHA YZ85 engine

PERIODIC MAINTENANCE AND ADJUSTMENT
7-9
7To install the spark plu
g
1. Clean the surface of the spark plug gasket and its mating sur-
face, and then wipe off any grime
from the spark plug threads.
2. Install the spark plug with the spark plug wrench, and then tight-
en it to the specified torque.
TIPIf 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.3. Install the spark plug cap.
EAU41449
Transmission oilThe transmission must be checked for
oil leakage before each ride. If any
leakage is found, have a Yamaha deal-
er check and repair the motorcycle. In
addition, the transmission oil must be
changed at the intervals specified in
the periodic maintenance and lubrica-
tion chart.1. Start the engine, warm it up for several minutes, and then turn it
off.
2. Place the motorcycle on a level surface and hold it in an upright
position.
3. Place an oil pan under the trans- mission case to collect the used
oil.
4. Remove the oil filler cap, the trans- mission oil drain bolt and its gas-
ket to drain the oil from the
transmission. 5. Install the drain bolt and its new
gasket, and then tighten the bolt
to the specified torque.
6. Refill with the specified amount of the recommended transmission
oil, and then install and tighten the
oil filler cap.
Tightenin g torque:
Spark plug: 20 Nm (2.0 m·kgf, 14 ft·lbf)
1. Transmission oil filler cap
2. Transmission oil drain bolt
3. GasketTightenin g torque:
Transmission oil drain bolt:
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Recommen ded transmission oil:
See page 9-1.
Oil chan ge quantity:
0.50 L (0.53 US qt, 0.44 Imp.qt)
1
2
3
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PERIODIC MAINTENANCE AND ADJUSTMENT
7-10
7
NOTICE
ECA10453
In or der to prevent clutch slip-
pa ge (since the transmission oil
also lu bricates the clutch), do
not mix any chemical additives.
Do not use oils with a d iesel
specification of “CD” or oils of a
hi gher quality than specifie d. In
a ddition, do not use oils lab eled
“ENERGY CONSERVING II” or
hi gher.
 Make sure that no forei gn mate-
rial enters the transmission.7. 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.
EAU20071
CoolantThe coolant level should be checked
before each ride. In addition, the cool-
ant must be changed at the intervals
specified in the periodic maintenance
and lubrication chart.
EAUM1296
To check the coolant level1. Place the vehicle on a level sur- face and hold it in an upright posi-
tion.TIPThe coolant level must be
checked on a cold engine since
the level varies with engine tem-
perature.
 Make sure that the vehicle is posi-
tioned straight up when checking
the coolant level. A slight tilt to the
side can result in a false reading.2. Remove the radiator cap and
check the coolant level in the radi-
ator. WARNING! Never attempt
to remove the ra diator cap
when the en gine is hot.
[EWA10382]
TIPThe coolant should be at the bottom of
the radiator filler neck. The level will
change with variation of engine tem-
perature.1. Radiator cap
1. Correct coolant level
1
1
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PERIODIC MAINTENANCE AND ADJUSTMENT
7-11
73. If the coolant is below the correct
coolant level, add coolant, and
then install the radiator cap.
NOTICE: If coolant is not avail-
a b le, use distille d water or soft
tap water instea d. Do not use
har d water or salt water since it
is harmful to the en gine. If water
has been used instead of cool-
ant, replace it with coolant as
soon as possi ble, otherwise the
coolin g system will not be pro-
tected against frost an d corro-
sion. If water has been adde d to
the coolant, have a Yamaha
d ealer check the antifreeze con-
tent of the coolant as soon as
possi ble, otherwise the effec-
tiveness of the coolant will be
re duce d.
[ECA10473]
EAUM1317
To change the coolant
1. Place the vehicle on a level sur- face and let the engine cool if nec-
essary.
2. Place a container under the en- gine to collect the used coolant. 3. Remove the coolant drain bolt and
its gasket, and then the radiator
cap to drain the cooling system.
WARNING! Never attempt to re-
move the ra diator cap when the
en gine is hot.
[EWA10382]
4. After the coolant is completely
drained, thoroughly flush the cool-
ing system with clean tap water.
5. Install the coolant drain bolt and its new gasket, and then tighten
the bolt to the specified torque.
6. Pour the recommended coolant into the radiator until it is full.
7. Install the radiator cap, start the engine, let it idle for several min-
utes, and then turn it off.
8. Remove the radiator cap to check the coolant level in the radiator. If
necessary, add sufficient coolant
1. Coolant drain bolt
2. Gasket
1. Radiator cap
1
2
1
Tightenin g torque:
Coolant drain bolt: 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Antifreeze/water mixture ratio: 1:1
Recommen ded antifreeze:
High-quality ethylene glycol anti-
freeze containing corrosion inhibi-
tors for aluminum engines
Coolant quantity: Radiator (including all routes):0.54 L (0.57 US qt, 0.48 Imp.qt)
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PERIODIC MAINTENANCE AND ADJUSTMENT
7-12
7
until it reaches the bottom of the
radiator filler neck, and then install
the radiator cap.
9. Start the engine, and then check the vehicle for coolant leakage. If
coolant is leaking, have a Yamaha
dealer check the cooling system.
EAU48392
Cleanin g the air filter elementThe air filter element should be cleaned
or replaced at the intervals specified in
the periodic maintenance and lubrica-
tion chart. Clean or, if necessary, re-
place the air filter element more
frequently if you are riding in unusually
wet or dusty areas.
1. Remove the seat. (See page 4-7.)
2. Remove the air filter case cover as shown. 3. Remove the air filter element by
removing the wing bolt and its
washer.
4. Remove the sponge material from the air filter element frame.1. Air filter case cover
1. Wing bolt
2. Washer
3. Air filter element
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PERIODIC MAINTENANCE AND ADJUSTMENT
7-14
7
10. Install the air filter case cover in
the original position as shown.
11. Install the seat.
EAU42111
A djustin g the car buretorThe carburetor is an important part of
the engine and requires very sophisti-
cated adjustment. Therefore, most
carburetor adjustments should be left
to a Yamaha dealer, who has the nec-
essary professional knowledge and ex-
perience. The adjustment described in
the following section, however, may be
serviced by the owner as part of rou-
tine maintenance.NOTICE
ECA10551
The car buretor has b een set and ex-
tensively teste d at the Yamaha fac-
tory. Chan gin g these settin gs
without sufficient technical knowl-
e dge may result in poor perfor-
mance of or damag e to the en gine.
EAU44391
A djustin g the en gine i dlin g
spee dThe engine idling speed must be ad-
justed when necessary.
1. Start the engine and thoroughly warm it up.
2. Turn the throttle stop screw until the engine runs at the lowest pos-
sible speed.
3. To increase the engine idling speed, turn the throttle stop screw
in direction (a). To decrease the
engine idling speed, turn the throt-
tle stop screw in direction (b).
1. Washer
1
1. Throttle stop screw
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PERIODIC MAINTENANCE AND ADJUSTMENT
7-15
7
EAU48433
Adjustin g the throttle grip free
playThe throttle grip free play should mea-
sure 3.0–5.0 mm (0.12–0.20 in) at the
inner edge of the throttle grip. Periodi-
cally check the throttle grip free play
and, if necessary, adjust it as follows.TIPThe engine idling speed must be cor-
rectly adjusted before checking and
adjusting the throttle grip free play.1. Slide the rubber cover back.
2. Loosen the locknut. 3. To increase the throttle grip free
play, turn the adjusting nut in di-
rection (a). To decrease the throt-
tle grip free play, turn the adjusting
nut in direction (b).
4. Tighten the locknut and then slide the rubber cover to its original po-
sition.
EAU41825
TiresTires are the only contact between the
vehicle and the road. Safety in all con-
ditions of riding depends on a relatively
small area of road contact. Therefore, it
is essential to maintain the tires in good
condition at all times and replace them
at the appropriate time with the speci-
fied tires.
Tire air pressure
The tire air pressure should be
checked and, if necessary, adjusted
before each ride.
WARNING
EWA14382
Operation of this vehicle with im-
proper tire pressure may cause se-
vere injury or death from loss of
control.  The tire air pressure must be
checked and a djuste d on col d
tires (i.e., when the temperature
of the tires equals the am bient
temperature).
1. Throttle grip free play
1. Locknut
2. Throttle grip free play adjusting nut
3. Rubber cover
2
3
(a)
(b)
1
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PERIODIC MAINTENANCE AND ADJUSTMENT
7-27
7
EAU23284
Checking the steerin gWorn or loose steering bearings may
cause danger. Therefore, the operation
of the steering must be checked as fol-
lows at the intervals specified in the
periodic maintenance and lubrication
chart.
1. Place a stand under the engine to raise the front wheel off the
ground. (See page 7-28 for more
information.) WARNING! To
avoi d injury, securely support
the vehicle so there is no dan ger
of it fallin g over.
[EWA10752]
2. Hold the lower ends of the front
fork legs and try to move them for-
ward and backward. If any free
play can be felt, have a Yamaha
dealer check or repair the steer-
ing.
EAU23292
Checkin g the wheel bearin gsThe front and rear wheel bearings must
be checked at the intervals specified in
the periodic maintenance and lubrica-
tion chart. If there is play in the wheel
hub or if the wheel does not turn
smoothly, have a Yamaha dealer
check the wheel bearings.
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PERIODIC MAINTENANCE AND ADJUSTMENT
7-28
7
EAU24351
Supporting the motorcycleSince this model is not equipped with a
centerstand, follow these precautions
when removing the front and rear
wheel or performing other mainte-
nance requiring the motorcycle to
stand upright. Check that the motorcy-
cle is in a stable and level position be-
fore starting any maintenance. A
strong wooden box can be placed un-
der the engine for added stability.
To service the front wheel
1. Stabilize the rear of the motorcy- cle by using a motorcycle stand
or, if an additional motorcycle
stand is not available, by placing a
jack under the frame in front of the
rear wheel.
2. Raise the front wheel off the ground by using a motorcycle
stand.
To service the rear wheel
Raise the rear wheel off the ground by
using a motorcycle stand or, if a motor-
cycle stand is not available, by placing a jack either under each side of the
frame in front of the rear wheel or under
each side of the swingarm.
EAU24361
Front wheel
EAU56371
To remove the front wheel
WARNING
EWA10822
To avoi
d injury, securely support the
vehicle so there is no dan ger of it
fallin g over.1. Loosen the axle nut.
2. Lift the front wheel off the ground
according to the procedure in the
previous section “Supporting the
motorcycle”.1. Washer
2. Axle nut
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