wheel YAMAHA YZ85 2003 User Guide

SPEC
2 - 13
MAINTENANCE SPECIFICATIONS
NOTE:
- marked portion shall be checked for torque tightening after break-in or before each race.Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb
Nipple (spoke)—64 3 0.3 2.2
Rear wheel sprocket M8 × 1.25 4 42 4.2 30
Rear brake caliper protector M6 × 1.0 1 10 1.0 7.2
Engine mounting:
Engine and frame (front) M10 × 1.25 1 69 6.9 50
Engine and frame (lower) M10 × 1.25 1 69 6.9 50
Pivot shaft and nut M12 × 1.25 1 63 6.3 45
Relay arm and frame M10 × 1.25 1 54 5.4 39
Relay arm and connecting rod M12 × 1.25 1 53 5.3 38
Connecting rod and swingarm M12 × 1.25 1 53 5.3 38
Rear shock absorber and frame M10 × 1.25 1 36 3.6 25
Rear shock absorber and relay arm M10 × 1.25 1 36 3.6 25
Rear frame (upper) M8 × 1.25 1 26 2.6 19
Rear frame (lower) M8 × 1.25 2 16 1.6 11
Swingarm and brake hose holder M5 × 0.8 4 1 0.1 0.7
Drive chain tensioner (upper) M8 × 1.25 1 23 2.3 17
Drive chain tensioner (lower) M6 × 1.0 1 10 1.0 7.2
Drive chain support M8 × 1.25 2 16 1.6 11
Drive chain support cover M6 × 1.0 1 7 0.7 5.1
Seal guard and swingarm M6 × 1.0 2 10 1.0 7.2
Fuel tank M6 × 1.0 2 7 0.7 5.1
Fuel cock M6 × 1.0 2 4 0.4 2.9
Fuel tank bracket and fuel tank M6 × 1.0 4 7 0.7 5.1
Seat set bracket and fuel tank M6 × 1.0 1 7 0.7 5.1
Radiator cover M6 × 1.0 3 4 0.4 2.9
Front fender M6 × 1.0 4 7 0.7 5.1
Rear fender M6 × 1.0 4 7 0.7 5.1
Flap guard M6 × 1.0 2 7 0.7 5.1
Side cover M6 × 1.0 2 7 0.7 5.1
Seat M6 × 1.0 2 7 0.7 5.1
Number plate M6 × 1.0 1 7 0.7 5.1

3 - 3
INSP
ADJ
MAINTENANCE INTERVALS
TIRE, WHEELS
Inspect air pressure, wheel run-out,
tire wear and spoke looseness
Retighten sprocket bolt
Inspect bearings
Replace bearings
Lubricate












Lithium base grease
THROTTLE, CONTROL CABLE
Check routing and connection
Inspect and Lubricate






Yamaha cable lube or
SAE 10W-30 motor oil ItemAfter
break-inEvery
raceEvery
third
raceEvery
fifth
raceAs re-
quiredRemarks

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 ~ 34
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.3-35
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 - 22
INSP
ADJ
SPROCKETS INSPECTION
1. Inspect:

Sprocket teeth a
Excessive wear → Replace.
NOTE:
Replace the drive sprocket, rear wheel
sprocket and drive chain as a set.
5PA30480
EC369002
DRIVE CHAIN INSPECTION
1. Remove:

Master link clip

Joint 1

Drive chain 2
5PA30490
2. Clean:

Drive chain
Place it in kerosene, and brush off as much
dirt as possible. Then remove the chain
from the kerosene and dry the chain.
5PA30500
3. Measure:

Drive chain length (10 links) a
Out of limit → Replace.
Drive chain length (10 links):
<Limit>: 122.1 mm (4.81 in)
5PA30510
4. Check:

Drive chain stiffness a
Clean and oil the chain and hold as illus-
trated.
Stiff → Replace drive chain.
5PA30520
SPROCKETS INSPECTION/
DRIVE CHAIN INSPECTION

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

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

4 - 46
ENG
EC4L3000
REMOVAL POINTS
Rotor
1. Remove:

Nut (rotor) 1

Washer 2
Use the rotor holding tool 3.
Rotor holding tool:
YU-1235/90890-01235
5PA41390
2. Remove:

Rotor 1
Use the flywheel puller 2.
NOTE:
When installing the flywheel puller, turn it
counterclockwise.
Flywheel puller:
YM-1189/90890-01189
5PA41400
EC4L4000
INSPECTION
EC4L4101
CDI magneto
1. Inspect:

Rotor inner surface a

Stator outer surface b
Damage → Inspect the crankshaft runout
and crankshaft bearing.
If necessary, replace CDI magneto and/or
stator.
5PA41410
EC4L4200
Woodruff key
1. Inspect:

Woodruff key 1
Damage → Replace.
5PA41420
CDI MAGNETO