2013 YAMAHA YZ85 engine

INSTRUMENT AND CONTROL FUNCTIONS
4-5
4
wash with soap and water. If gaso-
line spills on your clothing, change
your clothes.
EAU41360
Fuel tank breather hose Before operating the motorcycle:●
Check the fuel tank breather hose
connection.
●
Check the fuel tank breather hose
for cracks or damage, and replace
it if damaged.
●
Make sure that the end of the fuel
tank breather hose is not blocked,
and clean it if necessary.
TIPIf the fuel tank breather hose falls out,
reinstall it on the fuel tank cap with the
arrow mark on the one-way valve point-
ed downward as shown.
EAU41280
Fuel cock The fuel cock supplies fuel from the
tank to the carburetor while filtering it al-
so.
The fuel cock has two positions:
OFF
With the lever in this position, fuel will
not flow. Always return the lever to this
position when the engine is not running.
1. Fuel tank breather hose
2. One-way valve
1. Arrow mark positioned over “OFF”
U1SN81E0.book Page 5 Tuesday, June 12, 2012 3:17 PM

INSTRUMENT AND CONTROL FUNCTIONS
4-6
4ON
With the lever in this position, fuel flows
to the carburetor. Normal riding is done
with the lever in this position.
EAU13640
Starter (choke) knob Starting a cold engine requires a richer
air-fuel mixture, which is supplied by
the starter (choke).
Move the knob in direction (a) to turn on
the starter (choke).
Move the knob in direction (b) to turn off
the starter (choke).
EAU13650
Kickstarter To start the engine, fold out the kick-
starter lever, move it down lightly with
your foot until the gears engage, and
then push it down smoothly but force-
fully. This model is equipped with a pri-
mary kickstarter, allowing the engine to
be started in any gear if the clutch is
disengaged. However, shifting the
transmission into the neutral position
before starting is recommended.
1. Arrow mark positioned over “ON”
1. Starter (choke) knob
1. Kickstarter lever
U1SN81E0.book Page 6 Tuesday, June 12, 2012 3:17 PM

OPERATION AND IMPORTANT RIDING POINTS
6-1
6
EAU15951
Read the Owner’s Manual carefully to
become familiar with all controls. If
there is a control or function you do not
understand, ask your Yamaha dealer.
WARNING
EWA10271
Failure to familiarize yourself with
the controls can lead to loss of con-
trol, which could cause an accident
or injury.
EAU41307
Starting and warming up a
cold engine 1. Turn the fuel cock lever to “ON”.
2. Shift the transmission into the neu-tral position.
3. Turn the starter (choke) on and completely close the throttle. (See
page 4-6.)
4. Start the engine by pushing the kickstarter lever down.
5. When the engine is warm, turn the starter (choke) off.TIPThe engine is warm when it responds
quickly to the throttle with the starter
(choke) turned off.NOTICE
ECA11042
For maximum engine life, never ac-
celerate hard when the engine is
cold!
EAU16660
Starting a warm engine Follow the same procedure as for start-
ing a cold engine with the exception
that the starter (choke) is not required
when the engine is warm. Instead, start
the engine with the throttle slightly
open.TIPIf the engine does not start after several
kicks, try again with the throttle 1/4 to
1/2 open.
U1SN81E0.book Page 1 Tuesday, June 12, 2012 3:17 PM

OPERATION AND IMPORTANT RIDING POINTS
6-2
6
EAU16671
Shifting Shifting gears lets you control the
amount of engine power available for
starting off, accelerating, climbing hills,
etc.
The gear positions are shown in the il-
lustration.TIPTo shift the transmission into the neu-
tral position, press the shift pedal down
repeatedly until it reaches the end of its
travel, and then slightly raise it.
NOTICE
ECA10260
●
Even with the transmission in
the neutral position, do not
coast for long periods of time
with the engine off, and do not
tow the motorcycle for long dis-
tances. The transmission is
properly lubricated only when
the engine is running. Inade-
quate lubrication may damage
the transmission.
●
Always use the clutch while
changing gears to avoid damag-
ing the engine, transmission,
and drive train, which are not
designed to withstand the
shock of forced shifting.
EAU16690
To start out and accelerate1. Pull the clutch lever to disengage the clutch.
2. Shift the transmission into first gear.
3. Open the throttle gradually and si- multaneously release the clutch le-
ver slowly. 4. Once the motorcycle has reached
a speed high enough to change
gears, close the throttle, and at the
same time, quickly pull the clutch
lever in.
5. Shift the transmission into second gear. (Make sure not to shift the
transmission into the neutral posi-
tion.)
6. Open the throttle halfway and gradually release the clutch lever.
7. Follow the same procedure when shifting to the next gear.
EAU16710
To decelerate1. Close the throttle and apply both the front and the rear brakes to
slow the motorcycle.
2. Downshift through the gears and shift the transmission into the neu-
tral position when the motorcycle
is almost completely stopped.
1. Shift pedal
2. Neutral position
U1SN81E0.book Page 2 Tuesday, June 12, 2012 3:17 PM

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 thefuel 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 spark plug 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
U1SN81E0.book Page 3 Tuesday, June 12, 2012 3:17 PM

OPERATION AND IMPORTANT RIDING POINTS
6-4
6
These parts require about 30
minutes of break-in operation at
half-throttle or less. Observe the
condition of the engine carefully
during operation.
●
If any engine trouble should oc-
cur during the engine break-in
period, immediately have a
Yamaha dealer check the vehi- cle.
EAU17191
Parking When parking, stop the engine, and
then turn the fuel cock lever to “OFF”.
WARNING
EWA10311
●
Since the engine and exhaust
system can become very hot,
park in a place where pedestri-
ans or children are not likely to
touch them and be burned.
●
Do not park on a slope or on soft
ground, otherwise the vehicle
may overturn, increasing the
risk of a fuel leak and fire.
●
Do not park near grass or other
flammable materials which
might catch fire.
U1SN81E0.book Page 4 Tuesday, June 12, 2012 3:17 PM

PERIODIC MAINTENANCE AND ADJUSTMENT
7-1
7
EAU42073
Periodic inspection, adjustment, and lu-
brication will keep your vehicle in the
safest and most efficient condition pos-
sible. Safety is an obligation of the vehi-
cle owner/operator. The most important
points of vehicle inspection, adjust-
ment, and lubrication are explained on
the following pages.
The intervals given in the periodic
maintenance and lubrication chart
should be simply considered as a gen-
eral guide under normal riding condi-
tions. However, depending on the
weather, terrain, geographical location,
and individual use, the maintenance in-
tervals may need to be shortened.
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.
WARNING
EWA15122
Turn off the engine when performing
maintenance unless otherwise
specified.●
A running engine has moving
parts that can catch on body
parts or clothing and electrical
parts that can cause shocks or
fires.
●
Running the engine while ser-
vicing can lead to eye injury,
burns, fire, or carbon monoxide
poisoning – possibly leading to
death. See page 2-2 for more in-
formation about carbon monox-
ide.WARNING
EWA15460
Brake discs, calipers, drums, and
linings can become very hot during
use. To avoid possible burns, let
brake components cool before
touching them.
U1SN81E0.book Page 1 Tuesday, June 12, 2012 3:17 PM

PERIODIC MAINTENANCE AND ADJUSTMENT
7-8
7
EAU19613
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 accordance with the periodic mainte-
nance and lubrication chart. In addition,
the condition of the spark plug can re-
veal the condition of the engine.
To remove the spark plug1. Remove the spark plug cap.
2. Remove the spark plug as shown, with a spark plug wrench available
at a Yamaha dealer. To check the spark plug
1. Check that the porcelain insulator around the center electrode of the
spark plug is a medium-to-light tan
(the ideal color when the vehicle is
ridden normally).
TIPIf the spark plug shows a distinctly dif-
ferent color, the engine could be oper-
ating improperly. Do not attempt to
diagnose such problems yourself. In-
stead, have a Yamaha dealer check
the vehicle.
2. Check the spark plug for electrodeerosion and excessive carbon or
other deposits, and replace it if
necessary.
3. Measure the spark plug gap with a wire thickness gauge and, if nec-
essary, adjust the gap to specifica-
tion.
1. Spark plug cap
1. Spark plug wrench
Specified spark plug:NGK/BR10EG
1. Spark plug gap
Spark plug gap:0.5–0.6 mm (0.020–0.024 in)
U1SN81E0.book Page 8 Tuesday, June 12, 2012 3:17 PM