2010 YAMAHA YZ85 transmission

OPERATION AND IMPORTANT RIDING POINTS
6-3
6
EAU41503
Engine break-in
WARNING
EWA10321
Failure to properly maintain the ve-
hicle or performing maintenance ac-
tivities incorrectly may increase
your risk of injury or death during
service or while using the vehicle. If
you are not familiar with vehicle ser-
vice, have a Yamaha dealer perform
service.1. Before starting the engine, fill the
fuel tank with a break-in oil-fuel
mixture as follows.
2. Start and warm up the engine.
Check the operation of the controls
and the engine stop button. (See
page 4-1.)
3. Operate the motorcycle in the low-
er gears at moderate throttle open-
ings for five to eight minutes. Stop
the engine and check the sparkplug condition (see page 7-8); it
will show a rich condition during
break-in.
4. Allow the engine to cool. Restart
the engine and operate the motor-
cycle as in the step above for five
minutes. Then, very briefly shift to
the higher gears and check the
full-throttle response. Stop the en-
gine and check the spark plug.
5. After again allowing the engine to
cool, restart and run the motorcy-
cle for five more minutes. Full
throttle and the higher gears may
be used, but sustained full-throttle
operation should be avoided. Stop
the engine and check the spark
plug again.
6. Allow the engine to cool, remove
the cylinder head and cylinder, and
inspect the piston and cylinder.
Remove any high spots on the pis-
ton with #600-grit wet sandpaper.
Clean all components and careful-
ly reassemble the cylinder head
and cylinder.
7. Drain the break-in oil-fuel mixture
from the fuel tank and refill with the
specified mix. (See page 4-3.)8. Start the engine and check the op-
eration of the motorcycle through-
out its entire operating range. Stop
the engine and check the spark
plug condition. Restart the motor-
cycle and ride it for about 10 to 15
more minutes. The motorcycle will
now be ready to ride normally.
After the engine break-in period, thor-
oughly check the motorcycle for loose
parts, oil leakage and any other prob-
lems. Be sure to inspect and make ad-
justments thoroughly, especially cable
and drive chain slack and loose
spokes. In addition, check all fittings
and fasteners for looseness, and tight-
en if necessary.
NOTICE
ECA15560


When any of the following parts
have been replaced, they must
be broken in.
Cylinder or crankshaft:
About one hour of break-in op-
eration is necessary.
Piston, rings or transmission
gears:
Recommended 2-stroke engine oil:
See page 9-1.
Mixing ratio (gasoline to oil):
15:1
U5PA88E0.book Page 3 Tuesday, June 9, 2009 8:44 AM

PERIODIC MAINTENANCE AND ADJUSTMENT
7-3
7
√
5
*CylinderCheck cylinder for score marks or wear.
Clean.√
Replace.√ NO. ITEM ROUTINEAfter
break-inEvery
raceEvery
third raceEvery
fifth raceAs
required
6*ClutchCheck clutch housing, friction plates, clutch plates
and clutch springs for wear or damage.
Adjust.√ √
Replace.√
7*TransmissionChange the transmission oil.√
Check transmission for damage.√
Replace bearings.√
8*Shift forks, guide bars,
shift cam Replace if necessary. Check all parts for wear and damage.
√
9*Rotor nut
(flywheel magneto)Tighten.√√√
10*Kickstarter systemCheck idle gear for damage.
√
Replace if necessary.
11*Exhaust system Check exhaust pipe and muffler for carbon deposits.√ √
Clean.√
√
√ √
√ 12*CrankshaftCheck crankshaft for carbon deposits and damage.
Clean.
U5PA88E0.book Page 3 Tuesday, June 9, 2009 8:44 AM

PERIODIC MAINTENANCE AND ADJUSTMENT
7-9
7 To install the spark plug
1. Clean the surface of the spark plug
gasket and its mating surface, 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 speci-
fied torque as soon as possible.3. Install the spark plug cap.
EAU41445
Transmission oil The 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 lubrication
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 po-
sition.
3. Place an oil pan under the trans-
mission to collect the used oil.
4. Remove the oil filler cap, the drain
bolt and the gasket to drain the oil
from the transmission.5. Install a new gasket and the trans-
mission oil drain bolt, 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.
Tightening torque:
Spark plug:
20 Nm (2.0 m·kgf, 14 ft·lbf)
1. Transmission oil filler cap
2. Transmission oil drain bolt
3. Gasket
Tightening torque:
Transmission oil drain bolt:
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
21
2
3
U5PA88E0.book Page 9 Tuesday, June 9, 2009 8:44 AM

PERIODIC MAINTENANCE AND ADJUSTMENT
7-10
7
NOTICE
ECA10452


In order to prevent clutch slip-
page (since the transmission 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 mate-
rial enters the transmission.
7. Start the engine, and then let it idle
for several minutes while checking
the transmission for oil leakage. If
oil is leaking, immediately turn the
engine off and check for the cause.
EAU20070
Coolant The 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.
EAUM1294
To check the coolant level
1. Place the vehicle on a level sur-
face and hold it in an upright posi-
tion.
2. Remove the radiator cap and
check the coolant level in the radi-
ator. WARNING! Never attempt
to remove the radiator cap when
the engine is hot.
[EWA10381]
TIP

The coolant level must be checked
on a cold engine since the level
varies with engine temperature.


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.
TIPThe coolant should be at the bottom of
the radiator filler neck. The level will
change with variation of engine temper-
ature.3. If the coolant is below this level,
add coolant, and then install the
radiator cap. NOTICE: If coolant
Recommended transmission oil:
See page 9-1.
Oil change quantity:
0.50 L (0.53 US qt, 0.44 Imp.qt)
1. Radiator cap
1. Correct coolant level
U5PA88E0.book Page 10 Tuesday, June 9, 2009 8:44 AM

PERIODIC MAINTENANCE AND ADJUSTMENT
7-21
7
EAU22731
Changing the brake fluid Have a Yamaha dealer change the
brake fluid at the intervals specified in
the TIP after the periodic maintenance
and lubrication chart. In addition, have
the oil seals of the master cylinders and
calipers as well as the brake hoses re-
placed at the intervals listed below or
whenever they are damaged or leak-
ing.

Oil seals: Replace every two
years.


Brake hoses: Replace every four
years.
EAU22760
Drive chain slack The drive chain slack should be
checked before each ride and adjusted
if necessary.
EAU41410
To check the drive chain slack
1. Install the removable sidestand
and place the motorcycle on it.TIPWhen checking and adjusting the drive
chain slack, there should be no weight
on the motorcycle.2. Shift the transmission into the neu-
tral position.
3. Move the rear wheel by pushing
the motorcycle to locate the tight-
est portion of the drive chain, and
then measure the drive chain slack
as shown.4. If the drive chain slack is incorrect,
adjust it as follows.
EAU41482
To adjust the drive chain slack
1. Loosen the axle nut and the lock-
nut on each side of the swingarm.
2. To tighten the drive chain, turn the
drive chain slack adjusting bolt on
each side of the swingarm in direc-
tion (a). To loosen the drive chain,
turn the adjusting bolt on each side
of the swingarm in direction (b),
and then push the rear wheel for-
ward. NOTICE: Improper drive
chain slack will overload the en-
gine as well as other vital parts
of the motorcycle and can lead
Drive chain slack:
35.0–45.0 mm (1.38–1.77 in)
1. Drive chain slack
U5PA88E0.book Page 21 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

SPECIFICATIONS
9-2
9
Secondary reduction ratio:
YZ85 47/14 (3.357) (ZAF)
YZ85 48/14 (3.428)
(AUT)(BEL)(CHE)(DEU)(DNK)(ESP)(FIN)
(FRA)(GBR)(GRC)(IRL)(ITA)(NLD)(NOR)
(POL)(PRT)(SVN)(SWE)
YZ85LW 52/14 (3.714)
YZ85LWZ 52/14 (3.714)
YZ85Z 48/14 (3.428)
Transmission type:
Constant mesh 6-speed
Operation:
Left foot operation
Gear ratio:
1st:
27/11 (2.454)
2nd:
32/17 (1.882)
3rd:
26/17 (1.529)
4th:
22/17 (1.294)
5th:
26/23 (1.130)
6th:
25/25 (1.000)Chassis:Frame type:
Semi double cradle
Caster angle:
YZ85 26.30 °
YZ85LW 27.00 °
YZ85LWZ 27.00 °
YZ85Z 26.30 °Trail:
YZ85 88.0 mm (3.46 in)
YZ85LW 106.0 mm (4.17 in)
YZ85LWZ 106.0 mm (4.17 in)
YZ85Z 88.0 mm (3.46 in)
Front tire:Type:
With tube
Size:
YZ85 70/100-17 40M
YZ85LW 70/100-19 42M
YZ85LWZ 70/100-19 42M
YZ85Z 70/100-17 40M
Manufacturer/model:
YZ85 DUNLOP/D739FA (ZAF)
YZ85 DUNLOP/D756F
(AUT)(BEL)(CHE)(DEU)(DNK)(ESP)(FIN)
(FRA)(GBR)(GRC)(IRL)(ITA)(NLD)(NOR)
(POL)(PRT)(SVN)(SWE)
YZ85LW DUNLOP/D739FA (ZAF)
YZ85LW DUNLOP/D756F
(AUT)(BEL)(CHE)(DEU)(DNK)(ESP)(FIN)
(FRA)(GBR)(GRC)(IRL)(ITA)(NLD)(NOR)
(POL)(PRT)(SVN)(SWE)
YZ85LWZ DUNLOP/D756F
YZ85Z DUNLOP/D756FRear tire:Type:
With tube
Size:
YZ85 90/100-14 49M
YZ85LW 90/100-16 52M
YZ85LWZ 90/100-16 52M
YZ85Z 90/100-14 49MManufacturer/model:
DUNLOP/D756
Tire air pressure (measured on cold
tires):
Front:
100 kPa (1.00 kgf/cm², 15 psi)
Rear:
100 kPa (1.00 kgf/cm², 15 psi)
Front wheel:Wheel type:
Spoke wheel
Rim size:
YZ85 17x1.40
YZ85LW 19x1.40
YZ85LWZ 19x1.40
YZ85Z 17x1.40Rear wheel:Wheel type:
Spoke wheel
Rim size:
YZ85 14x1.60
YZ85LW 16x1.85
YZ85LWZ 16x1.85
YZ85Z 14x1.60Front brake:Type:
Single disc brake
Operation:
Right hand operation
Recommended fluid:
DOT 4Rear brake:Type:
Single disc brake
U5PA88E0.book Page 2 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