engine oil YAMAHA YZ85 2003 User Guide

3 - 7
INSP
ADJ
RADIATOR CAP INSPECTION
CAUTION:

Do not mix more than one type of ethyl-
ene glycol antifreeze containing corro-
sion inhibitors for aluminum engine.

Do not use water containing impurities or
oil.
7. Install:

Radiator cap
Start the engine and warm it up for a sev-
eral minutes.
8. Check:

Coolant level
Coolant level low → Add coolant. Handling notes of coolant:
The coolant is harmful so it should be han-
dled with special care.
WARNING

When coolant splashes to your eye.
Thoroughly wash your eye with water
and see your doctor.

When coolant splashes to your clothes.
Quickly wash it away with water and
then with soap.

When coolant is swallowed.
Quickly make him vomit and take him
to a doctor.
EC355000
RADIATOR CAP INSPECTION
1. Inspect:

Seal (radiator cap) 1

Valve and valve seat 2
Crack/damage → Replace.
Exist fur deposits 3 → Clean or replace.
5PA30050

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 engine mixing 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 - 23
INSP
ADJ
DRIVE CHAIN SLACK ADJUSTMENT
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 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.
5PAR0004
DRIVE CHAIN SUPPORT INSPECTION
1. Inspect:

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

4 - 23
ENG
NOTE:
When you purchase a cylinder, you cannot
designate its size. Choose the piston that
matches the above chart.
ASSEMBLY AND INSTALLATION
Piston ring and piston
1. Install:

Piston ring 1
NOTE:

Take care not to scratch the piston or dam-
age the piston ring.

Align the piston ring gap with the pin 2.

After installing the piston ring, check the
smooth movement of it.
5PA40620
2. Install:

Gasket (cylinder) 1

Small end bearing 2

Dowel pin 3
NOTE:

Apply the engine oil on the bearing (crank-
shaft and connecting rod) and connecting
rod big end washers.

Install the gasket with the seal print side
toward the crankcase.
5PA40630
CYLINDER HEAD, CYLINDER AND PISTON

4 - 24
ENG
3. Install:

Piston 1

Piston pin 2

Piston pin clip 3
NOTE:

The arrow a on the piston dome must point
to exhaust side.

Before installing the piston pin clip, cover the
crankcase with a clean rag to prevent the
piston pin clip from falling into the crankcase
cavity.
CAUTION:
Do not allow the clip open ends to meet the
piston pin slot b.
5PA40640
5PA40650
Cylinder head and cylinder
1. Apply:

Engine oil
To piston 1, piston ring 2 and cylinder
surface.
2. Install:

Cylinder 1
CAUTION:
Make sure the piston ring is properly posi-
tioned. Install the cylinder with one hand
while compressing the piston ring with the
other hand.
NOTE:
After installing, check the smooth movement of
the piston.
5PA40660
5PA40670
3. Install:

Nut (cylinder) 1
NOTE:
Tighten the nuts in stage, using a crisscross
pattern.
5PA40680
T R..28 Nm (2.8 m · kg, 20 ft · lb)
CYLINDER HEAD, CYLINDER AND PISTON

4 - 26
ENGCLUTCH AND PRIMARY DRIVEN GEAR
EC490000
CLUTCH AND PRIMARY DRIVEN GEAR
EC498000
CLUTCH PLATE AND FRICTION PLATE
5PA40720
Extent of removal:
1 Clutch plate and friction plate removal
Extent of removal Order Part name Q’ty Remarks
CLUTCH PLATE AND FRIC-
TION PLATE REMOVAL
Preparation for removal Drain the transmission oil. Refer to “TRANSMISSION OIL
REPLACEMENT” section in the CHAP-
TER 3.
Clutch cable Disconnect at engine side.
1 Clutch cover 1
2 Bolt (clutch spring) 5
3 Clutch spring 5
4 Pressure plate 1
5 Friction plate 7
6 Clutch plate 6
1

4 - 38
ENG
2. Install:

Spring guide 1
NOTE:
Slide the spring guide into the kick shaft, make
sure the groove a in the spring guide fits on
the stopper of the torsion spring.
5PA41120
3. Install:

Kick shaft assembly 1
NOTE:

Apply the transmission oil on the kick shaft.

Apply the lithium soap base grease on the
kick shaft stopper.

Slide the kick shaft assembly into the crank-
case, make sure the clip 2 and kick shaft
stopper a fit into their home positions b, c.5PA41130
4. Hook:

Torsion spring 1
NOTE:
Turn the torsion spring clockwise and hook
into the proper hole a in the crankcase.
5PA41140
Kick idle gear
1. Install:

Washer 1

Kick idle gear 2

Circlip 3
NOTE:

Apply the transmission oil on the kick idle
gear inner circumference.

Install the kick idle gear with its groove a
facing the engine.
5PA41150
KICK SHAFT, SHIFT SHAFT AND PRIMARY DRIVE GEAR