2002 YAMAHA YZ85 water pump

CHAPTER 3
REGULAR INSPECTION AND
ADJUSTMENTS
MAINTENANCE INTERVALS................... 3-1
PRE-OPERATION INSPECTION
AND MAINTENANCE................................ 3-4
ENGINE...................................................... 3-5
CHASSIS................................................. 3-16
ELECTRICAL........................................... 3-35
CHAPTER 4
ENGINE
SEAT, FUEL TANK
AND SIDE COVERS.................................. 4-1
EXHAUST PIPE AND SILENCER............. 4-2
RADIATOR................................................ 4-3
CARBURETOR AND REED VALVE......... 4-6
CYLINDER HEAD, CYLINDER
AND PISTON........................................... 4-15
CLUTCH AND PRIMARY
DRIVEN GEAR........................................ 4-26
KICK SHAFT, SHIFT SHAFT
AND PRIMARY DRIVE GEAR................. 4-33
WATER PUMP......................................... 4-41
CDI MAGNETO........................................ 4-45
ENGINE REMOVAL................................. 4-49
CRANKCASE AND CRANKSHAFT........ 4-53
TRANSMISSION, SHIFT CAM
AND SHIFT FORK................................... 4-59

1 - 3
GEN
INFO
IMPORTANT INFORMATION
EC130000
IMPORTANT INFORMATION
EC131010
PREPARATION FOR REMOVAL AND
DISASSEMBLY
1. Remove all dirt, mud, dust, and foreign
material before removal and disassembly.
When washing the machine with high pres-
sured water, cover the parts follows.
lSilencer end
lAir filter intake hole
lCrankcase cover hole at the bottom
lWater pump housing hole at the bottom
5PA10070
5PA10080
2. Use proper tools and cleaning equipment.
Refer to “SPECIAL TOOLS” section.
5PA10090
3. When disassembling the machine, keep
mated parts together. They include gears,
cylinders, pistons, and other mated parts
that have been “mated” through normal
wear. Mated parts must be reused as an
assembly or replaced.
5PA10100
4. During the machine disassembly, clean all
parts and place them in trays in the order of
disassembly. This will speed up assembly
time and help assure that all parts are cor-
rectly reinstalled.
5. Keep away from fire.
5PA10110

SPEC
2 - 6
MAINTENANCE SPECIFICATIONS
Reed valve:
Thickness “T” 0.42 mm (0.017 in) ----
Valve stopper height 7.4 ~ 7.8 mm (0.291 ~ 0.307 in) ----
Valve bending limit ---- 0.2 mm
(0.008 in)
Cooling:
Radiator core size
Width 117.8 mm (4.64 in) ----
Height 240 mm (9.45 in) ----
Thickness 32 mm (1.26 in) ----
Radiator cap opening pressure 95 ~ 125 kPa (0.95 ~ 1.25 kg/cm
2,
13.5 ~ 17.8 psi)----
Radiator capacity 0.32 L (0.28 lmp qt, 0.34 US qt) ----
Water pump
Type Single-suction centrifugal pump ----Item Standard Limit

SPEC
2 - 7
MAINTENANCE SPECIFICATIONS
Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb
Spark plug M14 ´ 1.25 1 20 2.0 14
Cylinder head (nut) M8 ´ 1.25 4 30 3.0 22
(stud bolt) M8 ´ 1.25 4 13 1.3 9.4
Cylinder (nut) M8 ´ 1.25 4 28 2.8 20
(stud bolt) M8 ´ 1.25 4 13 1.3 9.4
Impeller M8 ´ 1.25 1 14 1.4 10
Coolant drain bolt M6 ´ 1.0 1 10 1.0 7.2
Water pump housing M6 ´ 1.0 2 10 1.0 7.2
Air filter element M6 ´ 1.0 1 2 0.2 1.4
Carburetor joint M6 ´ 1.0 4 8 0.8 5.8
Reed valve M3 ´ 0.5 4 1 0.1 0.7
Exhaust pipe M6 ´ 1.0 2 12 1.2 8.7
Exhaust pipe stay M6 ´ 1.0 1 12 1.2 8.7
Silencer M6 ´ 1.0 1 12 1.2 8.7
Fiber (silencer) M6 ´ 1.0 2 10 1.0 7.2
Crankcase M6 ´ 1.0 11 8 0.8 5.8
Left crankcase cover M6 ´ 1.0 4 5 0.5 3.6
Right crankcase cover M6 ´ 1.0 4 10 1.0 7.2
Right crankcase cover M6 ´ 1.0 1 10 1.0 7.2
Clutch cover M6 ´ 1.0 6 10 1.0 7.2
Transmission oil drain bolt M8 ´ 1.25 1 10 1.0 7.2
Kickstarter crank M6 ´ 1.0 1 10 1.0 7.2
Primary drive gear M12 ´ 1.0 1 79 7.9 57
Clutch boss M12 ´ 1.0 1 70 7.0 50
Clutch spring M5 ´ 0.8 5 6 0.6 4.3
Drive sprocket M16 ´ 1.0 1 60 6.0 43
Crankcase bearing stopper M6 ´ 1.0 2 8 0.8 5.8
Shift pedal M6 ´ 1.0 1 10 1.0 7.2

4 - 33
ENGKICK SHAFT, SHIFT SHAFT AND PRIMARY DRIVE GEAR
KICK SHAFT, SHIFT SHAFT AND PRIMARY DRIVE GEAR
PRIMARY DRIVE GEAR
5PA40960
Extent of removal:
1 Primary drive gear removal
Extent of removal Order Part name Q’ty Remarks
PRIMARY DRIVE GEAR
REMOVAL
Drain the transmission oil. Refer to “TRANSMISSION OIL
REPLACEMENT” section in the CHAP-
TER 3.
Brake pedal
Radiator hose 2 Disconnect at water pump side.
1 Kickstarter crank 1
2 Right crankcase cover 1
3 Nut (primary drive gear) 1 Only loosening.
Refer to “REMOVAL POINTS”.
4 Primary driven gear 1 Refer to “CLUTCH AND PRIMARY
DRIVEN GEAR” section.
5 Primary drive gear 1
1

4 - 41
ENG
EC4G0000
WATER PUMP
5PA41240
Extent of removal:
1 Impeller shaft removal
2 Oil seal removal
Extent of removal Order Part name Q’ty Remarks
WATER PUMP DISASSEMBLY
Preparation for removal Right crankcase cover Refer to “KICK SHAFT, SHIFT SHAFT
AND PRIMARY DRIVE GEAR” section.
1 Water pump housing 1
2 Impeller 1
Refer to “REMOVAL POINTS”. 3 Washer 1
4 Impeller shaft 1
5 Bearing 1
Refer to “REMOVAL POINTS”.
6 Oil seal 2
1
2
WATER PUMP

4 - 42
ENG
REMOVAL POINTS
Impeller shaft
1. Remove:
lImpeller 1
lWasher 2
lImpeller shaft 3
NOTE:
Hold the impeller shaft on its width across the
flats a with spanners, etc. and remove the
impeller.
5PA41250
EC4G3210
Oil seal
NOTE:
lIt is not necessary to disassemble the water
pump, unless there is an abnormality such
as excessive change in coolant level, discol-
oration of coolant, or milky transmission oil.
lReplace the oil seal whenever it is remov-
aled.
1. Remove:
lBearing 1
2. Remove:
lOil seal 1
5PA41260
5PA41270
INSPECTION
EC444200
Impeller shaft
1. Inspect:
lImpeller shaft 1
Bend/wear/damage ® Replace.
Fur deposits ® Clean.
5PA41280
WATER PUMP

4 - 43
ENG
EC444300
Impeller shaft gear
1. Inspect:
lGear teeth a
Wear/damage ® Replace.
5PA41290
EC4H4600
Bearing
1. Inspect:
lBearing
Rotate inner race with a finger.
Rough spot/seizure ® Replace.
5PA41300
EC444400
Oil seal
1. Inspect:
lOil seal 1
Wear/damage ® Replace.
5PA41310
ASSEMBLY AND INSTALLATION
Oil seal
1. Install:
lOil seal 1
NOTE:
lApply the lithium soap base grease on the oil
seal lip.
lInstall the oil seal with its manufacture’s
marks or numbers facing the right crankcase
cover 2.
5PA41320
WATER PUMP