engine YAMAHA YZ85 2006 Owner's Guide

3 - 10
INSP
ADJTHROTTLE CABLE ADJUSTMENT/
THROTTLE LUBRICATION
EC35A001
THROTTLE CABLE ADJUSTMENT
1. Check:

Throttle grip free play a
Out of specification → Adjust.
Throttle grip free play
a:
3 ~ 5 mm (0.12 ~ 0.20 in)
5PA30110
2. Adjust:

Throttle grip free play
Throttle grip free play adjustment steps:

Loosen the locknut 1.

Turn the adjuster 2 until the specified free
play is obtained.

Tighten the locknut.
NOTE:
Before adjusting the throttle cable free play,
the engine idle speed should be adjusted.
WARNING
After adjusting, turn the handlebar to
right and left and make sure that the
engine idling does not run faster.
5PA30120
THROTTLE LUBRICATION
1. Remove:

Throttle cable cap 1
5PA30130
2. Apply:

Lithium soap base grease
On the throttle cable end a and tube guide
cable winding portion b.
3. Install:

Throttle cable cap
5PA30140
T R..1 Nm (0.1 m · kg, 0.7 ft · lb)

3 - 11
INSP
ADJ
AIR FILTER CLEANING
AIR FILTER CLEANING
NOTE:
Proper air filter maintenance is the biggest key
to preventing premature engine wear and
damage.
CAUTION:
Never run the engine without the air filter
element in place; this would allow dirt and
dust to enter the engine and cause rapid
wear and possible engine damage.
1. Remove:

Seat

Fitting bolt 1

Washer 2

Air filter element 3

Air filter guide 4
5PA30150
2. Clean:

Air filter element
Clean them with solvent.
NOTE:
After cleaning, remove the remaining solvent
by squeezing the element.
CAUTION:

Do not twist the element when squeezing
the element.

Leaving too much of solvent in the ele-
ment may result in poor starting.
5PA30160
3. Inspect:

Air filter element
Damage → Replace.
4. Apply:

Foam-air-filter oil or equivalent oil
To the element.
NOTE:
Squeeze out the excess oil. Element should be
wet but not dripping.

3 - 12
INSP
ADJ
TRANSMISSION OIL REPLACEMENT
5. Install:

Air filter guide 1
To air filter element 2.
5PA30170
6. Apply:

Lithium soap base grease
On the matching surface a on air filter ele-
ment.
5PA30180
7. Install:

Air filter element 1

Washer

Fitting bolt
NOTE:
Install the air filter element with its projection
a facing upward.
5PA30190
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
TRANSMISSION OIL REPLACEMENT
1. Start the engine and warm it up for several
minutes, and then turn off the engine and
wait for five minute.
2. Place the machine on a level place and
hold it on upright position by placing the
suitable stand under the engine.
3. Place a suitable container under the
engine.
4. Remove:

Oil drain bolt 1

Oil filler cap 2
Drain the transmission oil.
5PA30200

3 - 14
INSP
ADJ
PILOT AIR SCREW ADJUSTMENT
1. Adjust:

Pilot air screw 1
Adjustment steps:
NOTE:
To optimize the fuel flow at a smaller throttle
opening, each machine’s pilot air screw has
been individually set at the factory. Before
adjusting the pilot air screw, turn it in fully and
count the number of turns. Record this num-
ber as the factory-set number of turns out.

Turn in the pilot air screw until it is lightly
seated.

Turn out the pilot air screw by the speci-
fied number of turns.
Pilot air screw:
2 turns out (example)
5PA30230
ENGINE IDLING SPEED ADJUSTMENT
1. Start the engine and thoroughly warm it up.
2. Adjust:

Engine idling speed
Adjustment steps:

Turn the throttle stop screw 1 until the
engine runs at the lowest possible speed.
To increase idle speed → Turn the throt-
tle stop screw 1 in a.
To decrease idle speed → Turn the throt-
tle stop screw 1 out b.
5PA30240
EXHAUST PIPE INSPECTION
1. Inspect:

O-ring 1
Damage → Replace.
NOTE:
Install the O-rings with their depressed a fac-
ing inward.
5PA30250
PILOT AIR SCREW ADJUSTMENT/ENGINE IDLING
SPEED ADJUSTMENT/EXHAUST PIPE INSPECTION

3 - 23
INSP
ADJ
DRIVE CHAIN SLACK ADJUSTMENT
4. Check:

Drive chain stiffness a
Clean and oil the chain and hold as illus-
trated.
Stiff → Replace drive chain.
5PA30520
5. Install:

Drive chain 1

Joint 2

Master link clip 3
CAUTION:
Be sure to install the master link clip to the
direction as shown.
aTurning direction5PA30530
6. Lubricate:

Drive chain
Drive chain lubricant:
SAE 10W-30 motor oil or suit-
able chain lubricants
5PA30540
EC36A060
DRIVE CHAIN SLACK ADJUSTMENT
1. Elevate the rear wheel by placing the suit-
able stand under the engine.
2. Check:

Drive chain slack a
In the center between the drive axle and
rear wheel axle.
Out of specification → Adjust.
NOTE:
Before checking and/or adjusting, rotate the
rear wheel through several revolutions and
check the slack several times to find the tight-
est point. Check and/or adjust chain slack with
rear wheel in this “tight chain” position.
Drive chain slack:
35 ~ 45 mm (1.4 ~ 1.8 in)
5PA30550

3 - 24
INSP
ADJDRIVE CHAIN SUPPORT INSPECTION/
FRONT FORK INSPECTION
3. Adjust:

Drive chain slack
DRIVE CHAIN SUPPORT INSPECTION
1. Inspect:

Drive chain support wear limit
Limit reaches indicator a → Replace.
Refer to “SWINGARM” section in the
CHAPTER 5. Drive chain slack adjustment steps:

Loosen the axle nut 1 and locknuts 2.

Adjust chain slack by turning the adjusters 3.
To tighten
→ Turn adjuster
3 clockwise.
To loosen
→ Turn adjuster
3 counter-
clockwise and push wheel forward.

Turn each adjuster exactly the same
amount to maintain correct axle alignment.
(There are marks a on each side of chain
puller alignment.)
NOTE:
Turn the adjuster so that the chain is in line
with the sprocket, as viewed from the rear.
CAUTION:
Too small chain slack will overload the
engine and other vital parts; keep the
slack within the specified limits.

Tighten the axle nut while pushing down
the drive chain.
T R..
Axle nut:
90 Nm (9.0 m  kg, 65 ft  lb)

Tighten the locknuts.
T R..
Locknut:
16 Nm (1.6 m  kg, 11 ft  lb)
5PAR0004
5PAR0005
a a
EC36C000
FRONT FORK INSPECTION
1. Inspect:

Front fork smooth action
Operate the front brake and stroke the front
fork.
Unsmooth action/oil leakage → Repair or
replace.
5PA30570

3 - 25
INSP
ADJFRONT FORK OIL SEAL AND DUST SEAL CLEANING/
FRONT FORK INTERNAL PRESSURE BLEEDING/
FRONT FORK REBOUND DAMPING FORCE ADJUSTMENT
EC36D001
FRONT FORK OIL SEAL AND DUST SEAL
CLEANING
1. Remove:

Protector 1

Dust seal 2
NOTE:
Use a thin screw driver, and be careful not to
damage the inner fork tube and dust seal.5PA30580
2. Clean:

Dust seal a

Oil seal b
NOTE:

Clean the dust seal and oil seal after every
run.

Apply the lithium soap base grease on the
inner tube.
5PA30590
FRONT FORK INTERNAL PRESSURE
BLEEDING
NOTE:
If the front fork initial movement feels stiff dur-
ing a run, bleed the front fork internal pressure.
1. Elevate the front wheel by placing a suit-
able stand under the engine.
2. Remove the air bleed screw 1 and release
the internal pressure from the front fork.
3. Install:

Air bleed screw
EC36H002
FRONT FORK REBOUND DAMPING FORCE
ADJUSTMENT
1. Adjust:

Rebound damping force
By turning the adjuster 1.
Stiffer a → Increase the rebound damp-
ing force. (Turn the adjuster 1 in.)
Softer b → Decrease the rebound damp-
ing force. (Turn the adjuster 1 out.)
5PA30590
T R..1 Nm (0.1 m · kg, 0.7 ft · lb)
5PA30600

3 - 28
INSP
ADJREAR SHOCK ABSORBER SPRING PRELOAD
ADJUSTMENT
REAR SHOCK ABSORBER SPRING
PRELOAD ADJUSTMENT
1. Elevate the rear wheel by placing the suit-
able stand under the engine.
2. Remove:

Rear frame
3. Loosen:

Locknut 1
4. Adjust:

Spring preload
By turning the adjuster 2.
* For EUROPE
NOTE:

Be sure to remove all dirt and mud from
around the locknut and adjuster before
adjustment.

The length of the spring (installed) changes
1.5 mm (0.06 in) per turn of the adjuster.
CAUTION:
Never attempt to turn the adjuster beyond
the maximum or minimum setting.
5. Tighten:

Locknut
6. Install:

Rear frame (upper)

Rear frame (lower) Stiffer
→Increase the spring preload.
(Turn the adjuster
2 in.)
Softer
→Decrease the spring preload.
(Turn the adjuster
2 out.)
Spring length (installed)
a:
YZ85: 215 mm (8.46 in)
*212 mm (8.35 in)
YZ85LW: 207 mm (8.15 in)
*212 mm (8.35 in)
Extent of adjustment:
202.5 ~ 218.5 mm
(7.97 ~ 8.60 in)
5PA30630
5PA30640
T R..26 Nm (2.6 m · kg, 19 ft · lb)
T R..16 Nm (1.6 m · kg, 11 ft · lb)

3 - 32
INSP
ADJ
EC36T000
WHEEL INSPECTION
1. Inspect:

Wheel runout
Elevate the wheel and turn it.
Abnormal runout → Replace.
5PA30700
2. Inspect:

Bearing free play
Exist play → Replace.
5PA30710
STEERING HEAD INSPECTION AND
ADJUSTMENT
1. Elevate the front wheel by placing a suit-
able stand under the engine.
2. Check:

Steering stem
Grasp the bottom of the forks and gently
rock the fork assembly back and forth.
Free play → Adjust steering head.
3. Check:

Steering smooth action
Turn the handlebar lock to lock.
Unsmooth action → Adjust steering ring
nut.
5PA30720
5PA30730
WHEEL INSPECTION/
STEERING HEAD INSPECTION AND ADJUSTMENT

3 - 36
INSP
ADJ
ELECTRICAL/SPARK PLUG INSPECTION
EC370000
ELECTRICAL
EC371001
SPARK PLUG INSPECTION
1. Remove:

Spark plug
2. Inspect:

Electrode 1
Wear/damage → Replace.

Insulator color 2
Normal condition is a medium to light tan
color.
Distinctly different color → Check the
engine condition.
NOTE:
When the engine runs for many hours at low
speeds, the spark plug insulator will become
sooty, even if the engine and carburetor are in
good operating condition.
3. Measure:

Plug gap a
Use a wire gauge or thickness gauge.
Out of specification → Regap.
4. Clean the plug with a spark plug cleaner if
necessary.
Spark plug gap:
0.5 ~ 0.6 mm (0.020 ~ 0.024 in)
5PA30850
5. Tighten:

Spark plug
NOTE:

Before installing a spark plug, clean the gas-
ket surface and plug surface.

Finger-tighten a the spark plug before torqu-
ing to specification b.
5PA30860
T R..20 Nm (2.0 m · kg, 1.4 ft · lb)