2010 YAMAHA YZ85 engine

PERIODIC MAINTENANCE AND ADJUSTMENT
7-26
7
EAU23283
Checking the steering Worn 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 pe-
riodic maintenance and lubrication
chart.
1. Place a stand under the engine to
raise the front wheel off the
ground. (See page 7-26 for more
information.) WARNING! To
avoid injury, securely support
the vehicle so there is no danger
of it falling over.
[EWA10751]
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 steering.
EAU23291
Checking the wheel bearings The 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.
EAU24350
Supporting the motorcycle Since this model is not equipped with a
centerstand, follow these precautions
when removing the front and rear
wheel or performing other maintenance
requiring the motorcycle to stand up-
right. Check that the motorcycle is in a
stable and level position before starting
any maintenance. A strong wooden
box can be placed under the engine for
added stability.
To service the front wheel
1. Stabilize the rear of the motorcycle
by using a motorcycle stand or, if
an additional motorcycle stand is
not available, by placing a jack un-
der 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
U5PA88E0.book Page 26 Tuesday, June 9, 2009 8:44 AM

PERIODIC MAINTENANCE AND ADJUSTMENT
7-31
7
EAU41492
Troubleshooting charts Starting problems or poor engine performance
Check the fuel level in
the fuel tank.1. Fuel
There is
enough fuel.
There is
no fuel.
Supply fuel.
Operate the kickstarter.2. Compression
There is compression.
There is
no compression.Check the ignition.
Have a Yamaha dealer
check the vehicle.
Remove the spark plug
and check the electrodes.3. Ignition
Wet
DryWipe off with a dry cloth and correct the
spark plug gap, or replace the spark plug.
Have a Yamaha dealer check the vehicle.The engine does not start.
Have a Yamaha dealer check the vehicle.
Open the throttle halfway and operate
the kickstarter.
Check the compression.
The engine does not start.
Check the compression.
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PERIODIC MAINTENANCE AND ADJUSTMENT
7-32
7Engine overheating
WARNING
EWAT1040


Do not remove the radiator cap when the engine and radiator are hot. Scalding hot fluid and steam may be
blown out under pressure, which could cause serious injury. Be sure to wait until the engine has cooled.


Place a thick rag, like a towel, over the radiator cap, and then slowly rotate the cap counterclockwise to the de-
tent to allow any residual pressure to escape. When the hissing sound has stopped, press down on the cap
while turning it counterclockwise, and then remove the cap.
TIPIf coolant is not available, tap water can be temporarily used instead, provided that it is changed to the recommended coolant
as soon as possible.
Wait until the
engine has cooled.
Check the coolant level in the
radiator.
The coolant level
is OK.The coolant level is low.
Check the cooling system
for leakage.
Have a Yamaha dealer checkand repair the cooling system.Add coolant. (See TIP.)
Start the engine. If the engine overheats again,
have a
Yamaha dealer check
and repair the cooling system.
There is
leakage.
There is
no leakage.
U5PA88E0.book Page 32 Tuesday, June 9, 2009 8:44 AM

MOTORCYCLE CARE AND STORAGE
8-1
8
EAU37833
Matte color caution NOTICE
ECA15192
Some models are equipped with
matte colored finished parts. Be
sure to consult a Yamaha dealer for
advice on what products to use be-
fore cleaning the vehicle. Using a
brush, harsh chemical products or
cleaning compounds when cleaning
these parts will scratch or damage
their surface. Wax also should not
be applied to any matte colored fin-
ished parts.
EAU41356
Care While the open design of a motorcycle
reveals the attractiveness of the tech-
nology, it also makes it more vulnera-
ble. Rust and corrosion can develop
even if high-quality components are
used. A rusty exhaust pipe may go un-
noticed on a car, however, it detracts
from the overall appearance of a motor-
cycle. Frequent and proper care does
not only comply with the terms of the
warranty, but it will also keep your mo-
torcycle looking good, extend its life
and optimize its performance.
Before cleaning
1. Cover the muffler outlet with a
plastic bag after the engine has
cooled down.
2. Make sure that all caps and covers
as well as all electrical couplers
and connectors, including the
spark plug cap, are tightly in-
stalled.
3. Remove extremely stubborn dirt,
like oil burnt onto the crankcase,
with a degreasing agent and a
brush, but never apply such prod-ucts onto seals, gaskets, sprock-
ets, the drive chain and wheel
axles. Always rinse the dirt and de-
greaser off with water.
Cleaning
NOTICE
ECA10772


Avoid using strong acidic wheel
cleaners, especially on spoked
wheels. If such products are
used on hard-to-remove dirt, do
not leave the cleaner on the af-
fected area any longer than in-
structed. Also, thoroughly rinse
the area off with water, immedi-
ately dry it, and then apply a cor-
rosion protection spray.


Improper cleaning can damage
plastic parts (such as cowlings,
panels, windshields, headlight
lenses, meter lenses, etc.) and
the mufflers. Use only a soft,
clean cloth or sponge with wa-
ter to clean plastic. However, if
the plastic parts cannot be thor-
oughly cleaned with water, di-
luted mild detergent with water
may be used. Be sure to rinse
U5PA88E0.book Page 1 Tuesday, June 9, 2009 8:44 AM

MOTORCYCLE CARE AND STORAGE
8-2
8off any detergent residue using
plenty of water, as it is harmful
to plastic parts.


Do not use any harsh chemical
products on plastic parts. Be
sure to avoid using cloths or
sponges which have been in
contact with strong or abrasive
cleaning products, solvent or
thinner, fuel (gasoline), rust re-
movers or inhibitors, brake flu-
id, antifreeze or electrolyte.


Do not use high-pressure wash-
ers or steam-jet cleaners since
they cause water seepage and
deterioration in the following ar-
eas: seals (of wheel and swing-
arm bearings, fork and brakes),
electric components (couplers,
connectors, instruments,
switches and lights), breather
hoses and vents.


For motorcycles equipped with
a windshield: Do not use strong
cleaners or hard sponges as
they will cause dulling or
scratching. Some cleaning com-
pounds for plastic may leave
scratches on the windshield.Test the product on a small hid-
den part of the windshield to
make sure that it does not leave
any marks. If the windshield is
scratched, use a quality plastic
polishing compound after
washing.
After normal useRemove dirt with warm water, a mild
detergent, and a soft, clean sponge,
and then rinse thoroughly with clean
water. Use a toothbrush or bottlebrush
for hard-to-reach areas. Stubborn dirt
and insects will come off more easily if
the area is covered with a wet cloth for
a few minutes before cleaning.
After riding in the rain or near the seaSince sea salt is extremely corrosive,
carry out the following steps after each
ride in the rain or near the sea.
1. Clean the motorcycle with cold wa-
ter and a mild detergent, after the
engine has cooled down.
NOTICE: Do not use warm water
since it increases the corrosive
action of the salt.
[ECA10791]
2. Apply a corrosion protection spray
on all metal, including chrome- and
nickel-plated, surfaces to prevent
corrosion.
After cleaning
1. Dry the motorcycle with a chamois
or an absorbing cloth.
2. Immediately dry the drive chain
and lubricate it to prevent it from
rusting.
3. Use a chrome polish to shine
chrome, aluminum and stainless-
steel parts, including the exhaust
system.
4. To prevent corrosion, it is recom-
mended to apply a corrosion pro-
tection spray on all metal,
including chrome- and nickel-plat-
ed, surfaces.
5. Use spray oil as a universal clean-
er to remove any remaining dirt.
6. Touch up minor paint damage
caused by stones, etc.
7. Wax all painted surfaces.
8. Let the motorcycle dry completely
before storing or covering it.
U5PA88E0.book Page 2 Tuesday, June 9, 2009 8:44 AM

MOTORCYCLE CARE AND STORAGE
8-4
83. Drain the fuel tank and fuel lines,
and the carburetor float chamber
by loosening the drain bolt; this will
prevent fuel deposits from building
up.
4. Perform the following steps to pro-
tect the cylinder, piston rings, etc.
from corrosion.
a. Remove the spark plug cap
and spark plug.
b. Pour a teaspoonful of engine oil
into the spark plug bore.
c. Install the spark plug cap onto
the spark plug, and then place
the spark plug on the cylinder
head so that the electrodes are
grounded. (This will limit spark-
ing during the next step.)
d. Turn the engine over several
times with the starter. (This will
coat the cylinder wall with oil.)
e. Remove the spark plug cap
from the spark plug, and then
install the spark plug and the
spark plug cap. WARNING! To
prevent damage or injury
from sparking, make sure toground the spark plug elec-
trodes while turning the en-
gine over.
[EWA10951]
5. Lubricate all control cables and the
pivoting points of all levers and
brake pedal.
6. Check and, if necessary, correct
the tire air pressure, and then lift
the motorcycle so that both of its
wheels are off the ground. Alterna-
tively, turn the wheels a little every
month in order to prevent the tires
from becoming degraded in one
spot.
7. Cover the muffler outlet with a
plastic bag to prevent moisture
from entering it.TIPMake any necessary repairs before
storing the motorcycle.
U5PA88E0.book Page 4 Tuesday, June 9, 2009 8:44 AM

SPECIFICATIONS
9-1
9
Dimensions:Overall length:
YZ85 1818 mm (71.6 in)
(AUT)(BEL)(CHE)(DEU)(DNK)(ESP)(FIN)
(FRA)(GBR)(GRC)(IRL)(ITA)(NLD)(NOR)
(POL)(PRT)(SVN)(SWE)
YZ85 1821 mm (71.7 in) (ZAF)
YZ85LW 1903 mm (74.9 in)
YZ85LWZ 1903 mm (74.9 in)
YZ85Z 1818 mm (71.6 in)
Overall width:
758 mm (29.8 in)
Overall height:
YZ85 1161 mm (45.7 in)
YZ85LW 1205 mm (47.4 in)
YZ85LWZ 1205 mm (47.4 in)
YZ85Z 1161 mm (45.7 in)
Seat height:
YZ85 864 mm (34.0 in)
YZ85LW 904 mm (35.6 in)
YZ85LWZ 904 mm (35.6 in)
YZ85Z 864 mm (34.0 in)
Wheelbase:
YZ85 1255 mm (49.4 in)
(AUT)(BEL)(CHE)(DEU)(DNK)(ESP)(FIN)
(FRA)(GBR)(GRC)(IRL)(ITA)(NLD)(NOR)
(POL)(PRT)(SVN)(SWE)
YZ85 1258 mm (49.5 in) (ZAF)
YZ85LW 1286 mm (50.6 in)
YZ85LWZ 1286 mm (50.6 in)
YZ85Z 1255 mm (49.4 in)Ground clearance:
YZ85 351 mm (13.82 in)
YZ85LW 393 mm (15.47 in)
YZ85LWZ 393 mm (15.47 in)
YZ85Z 351 mm (13.82 in)
Weight:With oil and fuel:
YZ85 71.0 kg (157 lb)
YZ85LW 73.9 kg (163 lb)
YZ85LWZ 73.9 kg (163 lb)
YZ85Z 71.0 kg (157 lb)Engine:Engine type:
Liquid cooled 2-stroke
Cylinder arrangement:
Forward-inclined single cylinder
Displacement:
84 cm³
Bore × stroke:
47.5 × 47.8 mm (1.87 × 1.88 in)
Compression ratio:
8.20 :1
Starting system:
Kickstarter
Lubrication system:
PremixEngine oil:Type:
YAMALUBE 2-RTransmission oil:Type:
YAMALUBE 4 (10W-40) or SAE 10W-40
Oil change quantity:
0.50 L (0.53 US qt, 0.44 Imp.qt)
Cooling system:Radiator capacity (including all routes):
0.54 L (0.57 US qt, 0.48 Imp.qt)Air filter:Air filter element:
Wet elementFuel:Recommended fuel:
Premium unleaded gasoline only
Fuel tank capacity:
5.0 L (1.32 US gal, 1.10 Imp.gal)Carburetor:Type × quantity:
PWK28 x 1Spark plug (s):Manufacturer/model:
NGK/BR10EG
Spark plug gap:
0.5–0.6 mm (0.020–0.024 in)Clutch:Clutch type:
Wet, multiple-discTransmission:Primary reduction system:
Spur gear
Primary reduction ratio:
65/18 (3.611)
Secondary reduction system:
Chain drive
U5PA88E0.book Page 1 Tuesday, June 9, 2009 8:44 AM

INDEX
AAir filter element, cleaning .................... 7-12BBrake and clutch levers, checking and
lubricating ........................................... 7-23
Brake fluid, changing ............................ 7-21
Brake fluid level, checking .................... 7-20
Brake lever ............................................. 4-2
Brake pedal ............................................ 4-2
Brake pedal, checking and
lubricating ........................................... 7-24CCables, checking and lubricating .......... 7-23
Carburetor, adjusting ............................ 7-14
Care ........................................................ 8-1
Clutch lever............................................. 4-1
Clutch lever free play, adjusting ........... 7-17
Coolant ................................................. 7-10DDrive chain, cleaning and lubricating .... 7-22
Drive chain slack .................................. 7-21EEngine break-in ...................................... 6-3
Engine idling speed .............................. 7-14
Engine, starting a warm .......................... 6-1
Engine stop button.................................. 4-1FFront and rear brake pads, checking .... 7-19
Front brake lever free play, checking ... 7-18
Front fork, adjusting ................................ 4-7
Front fork, bleeding................................. 4-9
Front fork, checking .............................. 7-25
Fuel......................................................... 4-3
Fuel cock ................................................ 4-5Fuel tank breather hose .......................... 4-5
Fuel tank cap........................................... 4-3
HHandlebar switch..................................... 4-1IIdentification numbers ........................... 10-1KKickstarter ............................................... 4-6LLabels, location .......................................1-1MMatte color, caution .................................8-1
Model label ............................................ 10-1PParking ....................................................6-4
Part locations .......................................... 3-1
Periodic maintenance and lubrication
chart ......................................................7-2RRear suspension, lubricating ................. 7-25SSafety information ...................................2-1
Seat ......................................................... 4-7
Shifting ....................................................6-2
Shift pedal ............................................... 4-1
Shift pedal, checking ............................. 7-19
Shock absorber assembly, adjusting ...... 4-9
Sidestand .............................................. 4-12
Spark plug, checking ...............................7-8
Specifications .......................................... 9-1
Starter (choke) knob................................ 4-6
Starting and warming up a cold engine ... 6-1
Steering, checking.................................7-26
Storage....................................................8-3Supporting the motorcycle .................... 7-26
Swingarm pivots, lubricating ................. 7-24
TThrottle cable free play, adjusting ......... 7-14
Throttle grip and cable, checking and
lubricating ........................................... 7-23
Tires ...................................................... 7-15
Transmission oil ...................................... 7-9
Troubleshooting .................................... 7-29
Troubleshooting charts ......................... 7-31VVehicle identification number ................ 10-1WWheel bearings, checking..................... 7-26
Wheel (front) ......................................... 7-27
Wheel (rear) .......................................... 7-28
Wheels .................................................. 7-17
U5PA88E0.book Page 1 Tuesday, June 9, 2009 8:44 AM