Rear shock absorber YAMAHA YZ85 2004 Owners Manual

CHAPTER 5
CHASSIS
FRONT WHEEL AND REAR WHEEL....... 5-1
FRONT BRAKE AND REAR BRAKE....... 5-9
FRONT FORK.......................................... 5-27
HANDLEBAR........................................... 5-41
STEERING............................................... 5-46
SWINGARM............................................. 5-51
REAR SHOCK ABSORBER.................... 5-58
CHAPTER 6
ELECTRICAL
ELECTRICAL COMPONENTS
AND WIRING DIAGRAM........................... 6-1
IGNITION SYSTEM.................................... 6-2
CHAPTER 7
TUNING
ENGINE...................................................... 7-1
CHASSIS................................................. 7-10

GEN
INFO
1 - 16
TORQUE-CHECK POINTS
TORQUE-CHECK POINTS
Frame construction
Combined seat and fuel tank
Engine mounting
Steering Steering stem to
handlebar
Suspension Front Steering stem to front
fork
Rear For link type
Rear Installation of rear
shock absorber
Rear Installation of swin-
garm
Wheel Installation of wheel Front
Rear
Brake Front
Rear
Fuel systemFrame to rear frame
Fuel tank to frame
Frame to engine
Steering stem to upper bracket
Upper bracket to handlebar
Front fork to upper bracket
Front fork to lower bracket
Assembly of links
Link to frame
Link to rear shock absorber
Link to swingarm
Rear shock absorber to frame
Tightening of pivot shaft
Tightening of wheel axle
Tightening of wheel axle
Wheel to rear wheel sprocket
Brake caliper to front fork
Brake disc to wheel
Tightening of union bolt
Brake master cylinder to handlebar
Tightening of bleed screw
Brake caliper to bracket
Brake disc to wheel
Tightening of union bolt
Brake master cylinder to frame
Tightening of bleed screw
Fuel tank to fuel cock
NOTE:
Concerning the tightening torque, refer to
“MAINTENANCE SPECIFICATIONS” section
in the CHAPTER 2.

SPEC
2 - 3
GENERAL SPECIFICATIONS
Suspension:
Front suspension Telescopic fork
Rear suspension Swingarm (link type monocross suspension)
Shock absorber:
Front shock absorber Coil spring/air, oil damper
Rear shock absorber Coil spring/gas, oil damper
Wheel travel: YZ85 YZ85LW
Front wheel travel 275 mm (10.8 in)←
Rear wheel travel 282 mm (11.1 in) 287 mm (11.3 in)
Electrical:
Ignition system CDI magneto

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 Imp 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 Imp 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)

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
Drive chain puller adjust bolt and locknut M8 × 1.25 2 16 1.6 11
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 - 2
INSP
ADJ
MAINTENANCE INTERVALS
COOLING SYSTEM
Check coolant level and leakage
Check radiator cap operation
Replace coolant
Inspect hoses








Every two years
OUTSIDE NUTS AND BOLTS
Retighten



AIR FILTER
Clean and lubricate
Replace




Use foam air-filter oil or
equivalent oil
FRAME
Clean and inspect



FUEL TANK, COCK
Clean and inspect



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























Every one year
FRONT FORKS
Inspect and adjust
Replace oil
Replace oil seal









Suspension oil “01”
FRONT FORK OIL SEAL AND DUST
SEAL
Clean and lube


Lithium base grease
REAR SHOCK ABSORBER
Inspect and adjust
Lube
Retighten







(After
rain ride)


Molybdenum disulfide
grease
DRIVE CHAIN GUIDE, ROLLERS AND
SUPPORT
Inspect


SWINGARM
Inspect and retighten
Lube







Molybdenum disulfide
grease
RELAY ARM, CONNECTING ROD
Inspect and retighten
Lube







Molybdenum disulfide
grease
STEERING HEAD
Inspect free play and retighten
Clean and lube
Replace bearing







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 ~ 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 - 27
INSP
ADJ
REAR SHOCK ABSORBER INSPECTION

STANDARD POSITION:
This is the position which is back by the spe-
cific number of clicks from the fully turned-in
position.
CAUTION:
Do not force the adjuster past the minimum
or maximum extent of adjustment. The
adjuster may be damaged.
WARNING
Always adjust each front fork to the same
setting. Uneven adjustment can cause poor
handling and loss of stability.
3. Install:

Rubber cap
Extent of adjustment
Maximum Minimum
Fully turned in
position20 clicks out (from
maximum position)
Standard position:
YZ85: 10 clicks out
YZ85LW: 9 clicks out
EC36K000
REAR SHOCK ABSORBER INSPECTION
1. Inspect:

Swingarm smooth action
Abnormal noise/unsmooth action →
Grease the pivoting points or repair the piv-
oting points.
Damage/oil leakage → Replace.
5PA30620

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)