2002 YAMAHA YZ85 oil pressure

SPEC
2 - 8
MAINTENANCE SPECIFICATIONS
CHASSIS
YZ85
Item Standard Limit
Steering system:
Steering bearing type Taper roller bearing ----
Front suspension:
Front fork travel 275 mm (10.8 in) ----
Fork spring free length 430 mm (16.9 in) 425 mm (16.7 in)
Spring rate, STD K = 2.84 N/mm
(0.29 kg/mm, 16.2 lb/in)----
Optional spring Yes ----
Oil capacity318 cm
3
(11.2 lmp oz, 10.8 US oz) ----
Oil level 90 mm (3.54 in) ----

(From top of outer tube with inner
tube and damper rod fully com-
pressed without spring.)80 ~ 120 mm (3.15 ~ 4.72 in) ----
Oil grade Suspension oil “01” ----
Inner tube outer diameter 36 mm (1.42 in) ----
Front fork top end 24 mm (0.94 in) ----
Rear suspension: USA, CDN,
AUS, NZ, ZAEUROPE
Shock absorber travel 102 mm (4.02 in)¬----
Spring free length 220 mm (8.66 in)¬----
Fitting length 215 mm (8.46 in) 212 mm (8.35 in) ----
202.5 ~ 218.5 mm
(7.97 ~ 8.60 in)¬----
Spring rate, STD K = 49.0 N/mm
(5.00 kg/mm,
280.0 lb/in)K = 45.0 N/mm
(4.60 kg/mm,
257.6 lb/in)----
Optional spring Yes¬----
Enclosed gas pressure 1,000 kPa
(10 kg/cm
2,
142 psi)¬----
Swingarm:
Swingarm free play limit
End ---- 1.0 mm (0.04 in)

SPEC
2 - 10
MAINTENANCE SPECIFICATIONS
YZ85LW
Item Standard Limit
Steering system:
Steering bearing type Taper roller bearing ----
Front suspension:
Front fork travel 275 mm (10.8 in) ----
Fork spring free length 430 mm (16.9 in) 425 mm (16.7 in)
Spring rate, STD K = 2.94 N/mm
(0.30 kg/mm, 16.8 lb/in)----
Optional spring Yes ----
Oil capacity318 cm
3
(11.2 lmp oz, 10.8 US oz) ----
Oil level 90 mm (3.54 in) ----

(From top of outer tube with inner
tube and damper rod fully com-
pressed without spring.)80 ~ 120 mm (3.15 ~ 4.72 in) ----
Oil grade Suspension oil “01” ----
Inner tube outer diameter 36 mm (1.42 in) ----
Front fork top end Zero mm (Zero in) ----
Rear suspension: AUS, NZ EUROPE
Shock absorber travel 102 mm (4.02 in)¬----
Spring free length 220 mm (8.66 in)¬----
Fitting length 207 mm (8.15 in) 212 mm (8.35 in) ----
202.5 ~ 218.5 mm
(7.97 ~ 8.60 in)¬----
Spring rate, STD K = 51.0 N/mm
(5.20 kg/mm,
291.2 lb/in)K = 47.0 N/mm
(4.80 kg/mm,
268.8 lb/in)----
Optional spring Yes¬----
Enclosed gas pressure 1,000 kPa
(10 kg/cm
2,
142 psi)¬----
Swingarm:
Swingarm free play limit
End ---- 1.0 mm (0.04 in)

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
l
ll
l
l
ll
Lithium base grease
THROTTLE, CONTROL CABLE
Check routing and connection
Inspect and Lubricate
l
ll
lYamaha 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 ~ 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 - 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

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

5 - 60
CHAS
HANDLING NOTE
WARNING
This rear shock absorber is provided with a
separate type tank filled with high-pressure
nitrogen gas. To prevent the danger of
explosion, read and understand the follow-
ing information before handling the shock
absorber.
The manufacturer can not be held respon-
sible for property damage or personal
injury that may result from improper han-
dling.
1. Never tamper or attempt to disassem-
ble the cylinder or the tank.
2. Never throw the rear shock absorber
into an open flame or other high heat.
The rear shock absorber may explode
as a result of nitrogen gas expansion
and/or damage to the hose.
3. Be careful not to damage any part of
the gas tank. A damaged gas tank will
impair the damping performance or
cause a malfunction.
4. Take care not to scratch the contact
surface of the piston rod with the cylin-
der; or oil could leak out.
5. Never attempt to remove the plug at
the bottom of the nitrogen gas tank. It
is very dangerous to remove the plug.
6. When scrapping the rear shock
absorber, follow the instructions on
disposal.
NOTES ON DISPOSAL (YAMAHA DEALERS
ONLY)
Before disposing the rear shock absorber, be
sure to extract the nitrogen gas from valve 1.
Wear eye protection to prevent eye damage
from escaping gas and/or metal chips.
WARNING
To dispose of a damaged or worn-out rear
shock absorber, take the unit to your
Yamaha dealer for this disposal procedure.
5PA51880
REAR SHOCK ABSORBER

7 - 1
TUN
EC700000
TUNING
EC710000
ENGINE
Carburetor setting
lThe role of fuel is to cool the engine, and in
the case of a 2-stroke engine, to lubricate the
engine in addition to power generation.
Accordingly, if a mixture of air and fuel is too
lean, abnormal combustion will occur, and
engine seizure may result. If the mixture is
too rich, spark plugs will get wet with oil, thus
making it impossible to bring the engine into
full play or if the worst comes to the worst,
the engine may stall.
lThe richness of the air-fuel mixture required
for the engine will vary with atmospheric con-
ditions of the day and therefore, the settings
of the carburetor must be properly suited to
the atmospheric conditions (air pressure,
humidity and temperature).
lFinally, the rider himself must make a test
run and check his machine for conditions
(pick-up of engine speed, road surface con-
ditions) and for the discoloration of the spark
plug(s).
After taking these into consideration, he must
select the best possible carburetor settings.
* It is advisable to make a note of settings,
atmospheric conditions, road surface condi-
tion, lap-time, etc. so that the memorandum
can be used as a reference useful for future.
Atmospheric conditions and carburetor
settings
The air density (i.e., concentration of oxygen
in the air) determines the richness or lean-
ness of the air/fuel mixture. Therefore, refer
to the above table for mixture settings.
Air temp. HumidityAir
pressure
(altitude)Mixture Setting
High High Low (high) Richer Leaner
Low Low High (low) Leaner Richer
SETTING






7