2002 YAMAHA YZ85 steering

3 - 2
INSP
ADJ
MAINTENANCE INTERVALS
COOLING SYSTEM
Check coolant level and leakage
Check radiator cap operation
Replace coolant
Inspect hoses
ll
ll
l
Every two years
OUTSIDE NUTS AND BOLTS
Retighten
ll
AIR FILTER
Clean and lubricate
Replace
ll
lUse foam air-filter oil
FRAME
Clean and inspect
ll
FUEL TANK, COCK
Clean and inspect
ll
BRAKES
Adjust lever position and pedal height
Lubricate pivot point
Check brake disc surface
Check fluid level and leakage
Retighten brake disc bolts, caliper
bolts, master cylinder bolts and union
bolts
Replace pads
Replace brake fluid
l
l
l
l
ll
l
l
l
l
l
l
Every one year
FRONT FORKS
Inspect and adjust
Replace oil
Replace oil seal
l
ll
l
l
Suspension oil “01”
FRONT FORK OIL SEAL AND DUST
SEAL
Clean and lube
llLithium base grease
REAR SHOCK ABSORBER
Inspect and adjust
Lube
Retighten
l
ll
ll(After
rain ride)
l
Molybdenum disulfide
grease
CHAIN GUARD AND ROLLERS
Inspect
l
SWINGARM
Inspect and retighten
Lube
l
ll
l
Molybdenum disulfide
grease
RELAY ARM, CONNECTING ROD
Inspect and retighten
Lube
l
ll
l
Molybdenum disulfide
grease
STEERING HEAD
Inspect free play and retighten
Clean and lube
Replace bearing
ll
l
l
Lithium base grease ItemAfter
break-inEvery
raceEvery
third
raceEvery
fifth
raceAs re-
quiredRemarks


3

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 - 32
INSP
ADJ
2. Inspect:
lBearing 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:
lSteering stem
Grasp the bottom of the forks and gently
rock the fork assembly back and forth.
Free play ® Adjust steering head.
3. Check:
lSteering smooth action
Turn the handlebar lock to lock.
Unsmooth action ® Adjust steering ring
nut.
5PA30720
5PA30730
4. Adjust:
lSteering ring nut
Steering ring nut adjustment steps:
lRemove the number plate.
lRemove the handlebar and handlebar
upper bracket.
lLoosen the steering ring nut 1 using the
steering nut wrench 2.
Steering nut wrench:
YU-33975/90890-01403
5PA30740
STEERING HEAD INSPECTION AND ADJUSTMENT

3 - 33
INSP
ADJ
STEERING HEAD INSPECTION AND ADJUSTMENT
lTighten the steering ring nut 3 using
steering nut wrench 4.
NOTE:
Set the torque wrench to the steering nut
wrench so that they form a right angle.
Steering nut wrench:
YU-33975/90890-01403
T R..
Steering ring nut (initial tighten-
ing):
38 Nm (3.8 m • kg, 27 ft • lb)
lLoosen the steering ring nut one turn.
lRetighten the steering ring nut using the
steering nut wrench.
WARNING
Avoid over-tightening.
T R..
Steering ring nut (final tighten-
ing):
4 Nm (0.4 m • kg, 2.9 ft • lb)
lCheck the steering stem by turning it lock
to lock. If there is any binding, remove the
steering stem assembly and inspect the
steering bearings.
lInstall the upper bracket 5, steering stem
nut 6, handlebar 7, handlebar upper
holder 8 and number plate 9.
NOTE:
lThe upper handlebar holder should be
installed with the punched mark a for-
ward.
lInsert the end of fuel breather hose 0 into
the hole of the steering stem.
CAUTION:
First tighten the bolts on the front side of
the handlebar holder, and then tighten
the bolts on the rear side.
T R..
Steering stem nut:
115 Nm (11.5 m • kg, 85 ft • lb)
Handlebar upper holder:
27 Nm (2.7 m • kg, 19 ft • lb)
Pinch bolt (upper bracket):
22 Nm (2.2 m • kg, 16 ft • lb)
Number plate:
7 Nm (0.7 m • kg, 5.1 ft • lb)
5PA30750
5PA30760

5 - 45
CHAS
7. Install:
lEngine stop switch 1
lClutch lever holder 2
lBolts (clutch lever holder) 3
lClamp 4
NOTE:
The engine stop switch and clutch lever holder
should be installed according to the dimen-
sions shown.
5PA51420
T R..4 Nm (0.4 m · kg, 2.9 ft · lb)
5PA51430
8. Install:
lClutch cable 1
NOTE:
Apply the lithium soap base grease on the
clutch cable end.
5PA51440
9. Adjust:
lClutch lever free play
Refer to “CLUTCH ADJUSTMENT” section
in the CHAPTER 3.
10. Clamp the clamp portion a of the number
plate to the handlebar.
11. Insert the end of the fuel tank breather
hose 1 into the hole of the steering stem.
5PA51450
HANDLEBAR

5 - 46
CHAS
EC560000
STEERING
5PA51460
Extent of removal:
1 Lower bracket removal
2 Bearing removal
Extent of removal Order Part name Q’ty Remarks
STEERING REMOVAL
WARNING
Support the machine securely so there is nodanger of it falling over.
Refer to “HANDLEBAR” section. Preparation for removal Hold the machine by placing the
suitable stand under the engine.
Number plate
Handlebar
Cable guide
Front fender
1 Steering stem nut 1
2 Front fork 2 Refer to “FRONT FORK” section.
3 Upper bracket 1
4 Steering ring nut 1 Use special tool.
Refer to “REMOVAL POINTS”.
5 Lower bracket 1
6 Ball race cover 1
7 Upper bearing 1
8 Lower bearing 1 Refer to “REMOVAL POINTS”.
9 Ball race 2 Refer to “REMOVAL POINTS”.
2
1
STEERING

5 - 47
CHAS
EC563000
REMOVAL POINTS
Steering ring nut
1. Remove:
lSteering ring nut 1
Use the steering nut wrench 2.
WARNING
Support the steering stem so that it may
not fall down.
Steering nut wrench:
YU-33975/90890-01403
5PA51470
Lower bearing
1. Remove:
lLower bearing 1
Use the floor chisel 2.
CAUTION:
Take care not to damage the steering shaft
thread.
5PA51480
EC563400
Ball race
1. Remove:
lBall race 1
Remove the ball race using long rod 2 and
the hammer.
5PA51490
EC564000
INSPECTION
Steering stem
1. Inspect:
lSteering stem 1
Bend/damage ® Replace.
5PA51500
STEERING

5 - 48
CHAS
EC564101
Bearing and ball race
1. Wash the bearings and ball races with a
solvent.
2. Inspect:
lBearing 1
lBall race
Pitting/damage ® Replace bearings and
ball races as a set.
Install the bearing in the ball races. Spin
the bearings by hand. If the bearings hang
up or are not smooth in their operation in
the ball races, replace bearings and ball
races as a set.
5PA51510
EC565000
ASSEMBLY AND INSTALLATION
Lower bracket
1. Install:
lLower bearing 1
NOTE:
Apply the lithium soap base grease on the
bearing inner circumference.
5PA51520
2. Install:
lBall race
lUpper bearing 1
NOTE:
Apply the lithium soap base grease on the
bearing.
5PA51530
3. Install:
lLower bracket 1
NOTE:
Apply the lithium soap base grease on the
bearing.
5PA51540
STEERING