2010 YAMAHA YZ85 engine

INSTRUMENT AND CONTROL FUNCTIONS
4-5
4wash 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”
U5PA88E0.book Page 5 Tuesday, June 9, 2009 8:44 AM

INSTRUMENT AND CONTROL FUNCTIONS
4-6
4 ON
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
U5PA88E0.book Page 6 Tuesday, June 9, 2009 8:44 AM

INSTRUMENT AND CONTROL FUNCTIONS
4-9
4
EAU14791
Front fork bleeding
WARNING
EWA10200
Always bleed both fork legs, other-
wise poor handling and loss of sta-
bility may result.When riding in extremely rough condi-
tions, the air temperature and pressure
in the front fork will rise. This will in-
crease the spring preload and harden
the front suspension. If this occurs,
bleed the front fork as follows.
1. Elevate the front wheel by placing
a suitable stand under the engine.
TIPWhen bleeding the front fork, there
should be no weight on the front end of
the vehicle.2. Remove the bleed screws and al-
low all of the air to escape from
each fork leg.
3. Install the bleed screws.
EAU41332
Adjusting the shock absorber
assembly This shock absorber assembly is
equipped with a spring preload adjust-
ing nut, a rebound damping force ad-
justing screw and a compression
damping force adjusting screw.NOTICE
ECA10101
To avoid damaging the mechanism,
do not attempt to turn beyond the
maximum or minimum settings.Spring preload
Adjust the spring preload as follows.
1. Loosen the locknut.
1. Bleed screw
1. Locknut
2. Spring preload adjusting nut
U5PA88E0.book Page 9 Tuesday, June 9, 2009 8:44 AM

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.
EAU41305
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. NOTICE:
For maximum engine life, never
accelerate hard when the en-
gine is cold!
[ECA11041]
5. When the engine is warm, turn the
starter (choke) off.TIPThe engine is warm when it responds
normally to the throttle with the starter
(choke) turned off.
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.
U5PA88E0.book Page 1 Tuesday, June 9, 2009 8:44 AM

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 accelerate
1. 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 decelerate
1. 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 positionU5PA88E0.book Page 2 Tuesday, June 9, 2009 8:44 AM

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

OPERATION AND IMPORTANT RIDING POINTS
6-4
6These 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.
U5PA88E0.book Page 4 Tuesday, June 9, 2009 8:44 AM

PERIODIC MAINTENANCE AND ADJUSTMENT
7-1
7
EAU17241
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
EWA15121
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 2-1 for more in-
formation about carbon monox-
ide.
U5PA88E0.book Page 1 Tuesday, June 9, 2009 8:44 AM