2008 YAMAHA YZ85 check engine

TABLE OF CONTENTS
SAFETY INFORMATION .................. 1-1
Safe riding ....................................... 1-1
Location of important labels ........... 1-4
DESCRIPTION .................................. 2-1
Left view .......................................... 2-1
Right view ........................................ 2-2
Controls and instruments ................2-3
INSTRUMENT AND CONTROL
FUNCTIONS....................................... 3-1
Handlebar switch ............................ 3-1
Clutch lever .................................... 3-1
Shift pedal ......................................3-1
Brake lever ..................................... 3-2
Brake pedal .................................... 3-2
Fuel tank cap .................................. 3-3
Fuel ................................................ 3-3
Fuel tank breather hose ................. 3-5
Fuel cock ........................................ 3-5
Starter (choke) knob ....................... 3-6
Kickstarter ......................................3-6
Seat ................................................ 3-6
Adjusting the front fork ................... 3-7
Front fork bleeding ......................... 3-8
Adjusting the shock absorber
assembly ..................................... 3-9
Removable sidestand ................... 3-12
PRE-OPERATION CHECKS.............. 4-1
Pre-operation check list .................. 4-2OPERATION AND IMPORTANT
RIDING POINTS................................ 5-1
Starting and warming up a cold
engine ......................................... 5-1
Starting a warm engine .................. 5-1
Shifting ........................................... 5-2
Engine break-in .............................. 5-3
Parking ........................................... 5-4
PERIODIC MAINTENANCE AND
MINOR REPAIR................................. 6-1
Periodic maintenance and
lubrication chart .......................... 6-2
Checking the spark plug ................ 6-8
Transmission oil ............................. 6-9
Coolant ........................................ 6-10
Cleaning the air filter element ...... 6-12
Adjusting the carburetor ............... 6-14
Adjusting the engine idling
speed ........................................ 6-14
Adjusting the throttle cable free
play ........................................... 6-15
Tires ............................................. 6-15
Spoke wheels .............................. 6-17
Accessories and replacement
parts ......................................... 6-17
Adjusting the clutch lever free
play ........................................... 6-18
Checking the front brake lever
free play .................................... 6-18Checking the front and rear
brake pads ................................ 6-19
Checking the brake fluid level ...... 6-20
Changing the brake fluid .............. 6-21
Drive chain slack .......................... 6-21
Cleaning and lubricating the
drive chain ................................ 6-22
Checking and lubricating the
cables ....................................... 6-23
Checking and lubricating the
throttle grip and cable ............... 6-23
Checking and lubricating the
brake and shift pedals ............... 6-24
Checking and lubricating the
brake and clutch levers ............. 6-24
Lubricating the swingarm pivots ... 6-25
Lubricating the rear suspension ... 6-25
Checking the front fork ................. 6-25
Checking the steering .................. 6-26
Checking the wheel bearings ....... 6-27
Supporting the motorcycle ........... 6-27
Front wheel .................................. 6-28
Rear wheel ................................... 6-28
Troubleshooting ........................... 6-30
Troubleshooting charts ................. 6-31
MOTORCYCLE CARE AND
STORAGE.......................................... 7-1
Matte color caution ......................... 7-1
Care ............................................... 7-1
Storage ........................................... 7-3
U5PA86E0.book Page 1 Monday, April 9, 2007 3:16 PM

1-1
1
SAFETY INFORMATION
EAU41460
Safe riding

Always make pre-operation
checks. Careful checks may help
prevent an accident.


This motorcycle is designed for off-
road use only, therefore, it is illegal
to operate it on public streets,
roads, or highways, even a dirt or
gravel one. Off-road use on public
lands may be illegal. Please check
local regulations before riding.


This motorcycle is designed to car-
ry the operator only. No passen-
gers.


Many accidents involve inexperi-
enced operators.
Make sure that the operator is
qualified and that you only lend
your motorcycle to other quali-
fied operators.
Know your skills and limits.
Staying within your limits may
help you to avoid an accident.


Many accidents have been caused
by error of the motorcycle opera-
tor. A typical error made by the op-
erator is veering wide on a turn
due to EXCESSIVE SPEED or un-dercornering (insufficient lean an-
gle for the speed). Never travel
faster than warranted by condi-
tions.


Ride cautiously in unfamiliar ar-
eas. You may encounter hidden
obstacles that could cause an ac-
cident.


The posture of the operator is im-
portant for proper control. The op-
erator should keep both hands on
the handlebar and both feet on the
operator footrests during operation
to maintain control of the motor-
cycle.


Never ride under the influence of
alcohol or other drugs.


Be sure the transmission is in neu-
tral before starting the engine.
Protective apparel
The majority of fatalities from motor-
cycle accidents are the result of head
injuries. The use of a safety helmet is
the single most critical factor in the pre-
vention or reduction of head injuries.


Always wear an approved helmet.


Wear a face shield or goggles.
Wind in your unprotected eyes
could contribute to an impairment
of vision that could delay seeing a
hazard.


The use of a jacket, heavy boots,
trousers, gloves, etc., is effective in
preventing or reducing abrasions
or lacerations.


Never wear loose-fitting clothes,
otherwise they could catch on the
control levers, footrests, or wheels
and cause injury or an accident.


Never touch the engine or exhaust
system during or after operation.
They become very hot and can
cause burns. Always wear protec-
tive clothing that covers your legs,
ankles, and feet.
Modifications
Modifications made to this motorcycle
not approved by Yamaha, or the re-
moval of original equipment, may ren-
der the motorcycle unsafe for use and
may cause severe personal injury.
Modifications may also make your
motorcycle illegal to use.
U5PA86E0.book Page 1 Monday, April 9, 2007 3:16 PM

SAFETY INFORMATION
1-2
1Loading and accessories
Adding accessories to your motorcycle
can adversely affect stability and han-
dling if the weight distribution of the
motorcycle is changed. To avoid the
possibility of an accident, use extreme
caution when adding accessories to
your motorcycle. Use extra care when
riding a motorcycle that has added ac-
cessories. Here are some general
guidelines to follow if adding accesso-
ries to your motorcycle:
Loading


Accessory weight should be kept
as low and close to the motorcycle
as possible. Make sure to distrib-
ute the weight as evenly as possi-
ble on both sides of the motorcycle
to minimize imbalance or instabili-
ty.


Shifting weights can create a sud-
den imbalance. Make sure that ac-
cessories are securely attached to
the motorcycle before riding.
Check accessory mounts fre-
quently.


Never attach any large or heavy
items to the handlebar, front fork,
or front fender.Accessories
Genuine Yamaha accessories have
been specifically designed for use on
this motorcycle. Since Yamaha cannot
test all other accessories that may be
available, you must personally be re-
sponsible for the proper selection, in-
stallation and use of non-Yamaha
accessories. Use extreme caution
when selecting and installing any ac-
cessories.
Keep these guidelines in mind for
mounting accessories in addition to
those provided under “Loading”.

Never install accessories or that
would impair the performance of
your motorcycle. Carefully inspect
the accessory before using it to
make sure that it does not in any
way reduce ground clearance or
cornering clearance, limit suspen-
sion travel, steering travel or con-
trol operation.
Accessories fitted to the handle-
bar or the front fork area can
create instability due to improper
weight distribution or aerody-
namic changes. If accessories
are added to the handlebar orfront fork area, they must be as
lightweight as possible and
should be kept to a minimum.
Bulky or large accessories may
seriously affect the stability of
the motorcycle due to aerody-
namic effects. Wind may at-
tempt to lift the motorcycle, or
the motorcycle may become un-
stable in cross winds.
Certain accessories can dis-
place the operator from his or
her normal riding position. This
improper position limits the free-
dom of movement of the opera-
tor and may limit control ability,
therefore, such accessories are
not recommended.


Use caution when adding electri-
cal accessories. If electrical acces-
sories exceed the capacity of the
motorcycle’s electrical system an
electric failure could result, which
could cause a dangerous loss of
engine power.
U5PA86E0.book Page 2 Monday, April 9, 2007 3:16 PM

INSTRUMENT AND CONTROL FUNCTIONS
3-5
3
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.
NOTE:If 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.ON
With the lever in this position, fuel flows
to the carburetor. Normal riding is done
with the lever in this position.
1. Fuel tank breather hose
2. One-way valve
1. Arrow mark positioned over “OFF”
1. Arrow mark positioned over “ON”
U5PA86E0.book Page 5 Monday, April 9, 2007 3:16 PM

INSTRUMENT AND CONTROL FUNCTIONS
3-8
3 2. To increase the compression
damping force and thereby harden
the compression damping, turn the
adjusting screw on each fork leg in
direction (a). To decrease the
compression damping force and
thereby soften the compression
damping, turn the adjusting screw
on each fork leg in direction (b).
3. Install the rubber cap.
CAUTION:
ECA10100
Never attempt to turn an adjusting
mechanism beyond the maximum orminimum settings.
NOTE:Although the total number of clicks of a
damping force adjusting mechanism
may not exactly match the above spec-
ifications due to small differences in
production, the actual number of clicks
always represents the entire adjusting
range. To obtain a precise adjustment,
it would be advisable to check the num-
ber of clicks of each damping force ad-
justing mechanism and to modify thespecifications as necessary.
EAU14790
Front fork bleeding 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.NOTE:When bleeding the front fork, there
should be no weight on the front end ofthe vehicle.
2. Remove the bleed screws and al-
low all of the air to escape from
each fork leg.
Compression damping setting:
Minimum (soft):
20 click(s) in direction (b)*
Standard:
YZ85(X): 10 click(s) in direction
(b)*
YZ85LW(X): 9 click(s) in direction
(b)*
Maximum (hard):
1 click(s) in direction (b)*
* With the adjusting screw fully turned
in direction (a)
1. Bleed screw
U5PA86E0.book Page 8 Monday, April 9, 2007 3:16 PM

OPERATION AND IMPORTANT RIDING POINTS
5-3
5
EAU41502
Engine break-in 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 3-1.)
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 6-8); 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 motor-
cycle 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.
WARNING
EWA10320
If you are not familiar with mainte-
nance work, have a Yamaha dealerdo it for you.
7. Drain the break-in oil-fuel mixture
from the fuel tank and refill with the
specified mix. (See page 3-3.)
8. Start the engine and check the op-
eration of the motorcycle through-
out its entire operating range. Stop
the engine and check the sparkplug 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.
CAUTION:
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:
These parts require about 30
minutes of break-in operation at
half-throttle or less. Observe the
condition of the engine carefully
during operation.
Recommended 2-stroke engine oil:
See page 8-1.
Mixing ratio (gasoline to oil):
15:1
U5PA86E0.book Page 3 Monday, April 9, 2007 3:16 PM

OPERATION AND IMPORTANT RIDING POINTS
5-4
5


If any engine trouble should oc-
cur during the engine break-in
period, immediately have a
Yamaha dealer check the vehi-cle.
EAU17190
Parking When parking, stop the engine, and
then turn the fuel cock lever to “OFF”.
WARNING
EWA10310


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.


Do not park on a slope or on soft
ground, otherwise the vehiclemay overturn.
U5PA86E0.book Page 4 Monday, April 9, 2007 3:16 PM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-8
6
EAU19612
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 plug
1. 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).
NOTE:
If 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 checkthe vehicle.2. Check the spark plug for electrode
erosion and excessive carbon or
other deposits, and replace it if
necessary.
To install the spark plug
1. 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/BR10EG1. Spark plug gapSpark plug gap:
0.5–0.6 mm (0.020–0.024 in)
U5PA86E0.book Page 8 Monday, April 9, 2007 3:16 PM