2002 YAMAHA YZ85 engine oil

2 - 16
SPEC
EC240000
CABLE ROUTING DIAGRAM
1Hose guide
2Brake hose
3Throttle cable
4Fuel tank breather hose
5Engine stop switch lead
6CDI magneto lead
7Clamp
8Carburetor breather hose
9Carburetor overflow hose
0Transmission oil breather hose
ARadiator breather hose
BClutch cable
CSpark plug leadDCable guide
EBrake hose holder
ÈPass the fuel tank breather hose between the
handlebar and tension bar, then insert its end
into the hole of the steering stem.
ÉFasten the ground lead together with the ignition
coil.
ÊClamp the brake hose with the brake hose
holder.
ËFit the brake hose into the guides of the protec-
tor.
CABLE ROUTING DIAGRAM

3 - 4
INSP
ADJ
PRE-OPERATION INSPECTION AND MAINTENANCE
EC320000
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating
condition.
Before using this machine, check the following points.
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
CoolantCheck that coolant is filled up to the radiator cap.
Check the cooling system for leakage.P.3-5 ~ 9
FuelCheck that a fresh mixture of oil and gasoline is filled in the fuel
tank. Check the fuel line for leakage.P.1-12
Transmission oilCheck that the oil level is correct. Check the crankcase for leak-
age.P.3-12 ~ 13
Gear shifter and clutchCheck that gears can be shifted correctly in order and that the
clutch operates smoothly.P.3-9
Throttle grip/HousingCheck that the throttle grip operation and free play are correctly
adjusted. Lubricate the throttle grip and housing, if necessary.P.3-10
Brakes Check the play of front brake and effect of front and rear brake. P.3-16 ~ 21
Drive chainCheck drive chain slack and alignment. Check that the drive
chain is lubricated properly.P.3-22 ~ 24
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P.3-31 ~ 32
SteeringCheck that the handlebar can be turned smoothly and have no
excessive play.P.3-32 ~ 33
Front forks and rear shock
absorberCheck that they operate smoothly and there is no oil leakage. P.3-24 ~ 30
Cables (wires)Check that the clutch and throttle cables move smoothly. Check
that they are not caught when the handlebars are turned or
when the front forks travel up and down.—
Exhaust pipe and silencerCheck that the exhaust pipe is tightly mounted and has no
cracks.P.4-2
Rear wheel sprocket Check that the rear wheel sprocket tightening bolt is not loose. P.3-22
Lubrication Check for smooth operation. Lubricate if necessary. P.3-34
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P.1-16
Lead connectorsCheck that the CDI magneto, CDI unit, and ignition coil are con-
nected tightly.P.1-6
SettingsIs the machine set suitably for the condition of the racing course
and weather or by taking into account the results of test runs
before racing? Are inspection and maintenance completely
done?P.7-1 ~ 19

3 - 7
INSP
ADJ
RADIATOR CAP INSPECTION
CAUTION:
lDo not mix more than one type of ethyl-
ene glycol antifreeze containing corro-
sion inhibitors for aluminum engine.
lDo not use water containing impurities or
oil.
7. Install:
lRadiator cap
Start the engine and warm it up for a sev-
eral minutes.
8. Check:
lCoolant level
Coolant level low ® Add coolant. Handling notes of coolant:
The coolant is harmful so it should be han-
dled with special care.
WARNING
lWhen coolant splashes to your eye.
Thoroughly wash your eye with water
and see your doctor.
lWhen coolant splashes to your clothes.
Quickly wash it away with water and
then with soap.
lWhen coolant is swallowed.
Quickly make him vomit and take him
to a doctor.
EC355000
RADIATOR CAP INSPECTION
1. Inspect:
lSeal (radiator cap) 1
lValve 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:
lSeat
lFitting bolt 1
lWasher 2
lAir filter element 3
lAir filter guide 4
5PA30150
2. Clean:
lAir filter element
Clean them with solvent.
NOTE:
After cleaning, remove the remaining solvent
by squeezing the element.
CAUTION:
lDo not twist the element when squeezing
the element.
lLeaving too much of solvent in the ele-
ment may result in poor starting.
5PA30160
3. Inspect:
lAir filter element
Damage ® Replace.
4. Apply:
lFoam-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:
lAir filter guide 1
To air filter element 2.
5PA30170
6. Apply:
lLithium soap base grease
On the matching surface a on air filter ele-
ment.
5PA30180
7. Install:
lAir filter element 1
lWasher
lFitting 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:
lOil drain bolt 1
lOil filler cap 2
Drain the transmission oil.
5PA30200

3 - 23
INSP
ADJ
DRIVE CHAIN SLACK ADJUSTMENT
5. Install:
lDrive chain 1
lJoint 2
lMaster link clip 3
CAUTION:
Be sure to install the master link clip to the
direction as shown.
aTurning direction5PA30530
6. Lubricate:
lDrive 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:
lDrive 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
ADJFRONT FORK INSPECTION/
FRONT FORK OIL SEAL AND DUST SEAL CLEANING
3. Adjust:
lDrive chain slack
Drive chain slack adjustment steps:
lLoosen the axle nut 1 and locknuts 2.
lAdjust chain slack by turning the adjusters 3.
To tighten
® Turn adjuster
3 clockwise.
To loosen
® Turn adjuster
3 counter-
clockwise and push wheel forward.
lTurn 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.
lTighten the axle nut while pushing down
the drive chain.
T R..
Axle nut:
110 Nm (11.0 m • kg, 80 ft • lb)
lTighten the locknuts.
5PA30560
EC36C000
FRONT FORK INSPECTION
1. Inspect:
lFront fork smooth action
Operate the front brake and stroke the front
fork.
Unsmooth action/oil leakage ® Repair or
replace.
5PA30570
EC36D001
FRONT FORK OIL SEAL AND DUST SEAL
CLEANING
1. Remove:
lProtector 1
lDust seal 2
NOTE:
Use a thin screw driver, and be careful not to
damage the inner fork tube and dust seal.5PA30580

3 - 25
INSP
ADJFRONT FORK INTERNAL PRESSURE BLEEDING/FRONT
FORK REBOUND DAMPING FORCE ADJUSTMENT
2. Clean:
lDust seal a
lOil seal b
NOTE:
lClean the dust seal and oil seal after every
run.
lApply 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:
lAir bleed screw
5PA30590
T R..1 Nm (0.1 m · kg, 0.7 ft · lb)
EC36H002
FRONT FORK REBOUND DAMPING FORCE
ADJUSTMENT
1. Adjust:
lRebound 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.)
Extent of adjustment
Maximum Minimum
Fully turned in
position20 clicks out (from
maximum position)
5PA30600