2000 YAMAHA YZ426F coolant

3 - 7
INSP
ADJ

RADIATOR CAP INSPECTION
CAUTION:

l
Do not mix more than one type of ethyl-
ene glycol antifreeze containing corro-
sion inhibitors for aluminum engine.
l
Do not use water containing impurities or
oil.
7. Install:
l
Radiator cap
Start the engine and warm it up for a
several minutes.
8. Check:
lCoolant level
Coolant level low ® Add coolant. Handling notes of coolant:
The coolant is harmful so it should be han-
dled with special care.
WARNING
lWhen coolant splashes to your eye.
Thoroughly wash your eye with water
and see your doctor.
lWhen coolant splashes to your
clothes.
Quickly wash it away with water and
then with soap.
lWhen coolant is swallowed.
Quickly make him vomit and take him
to a doctor.
EC355000
RADIATOR CAP INSPECTION
1. Inspect:
lSeal (radiator cap) 1
lValve and valve seat 2
Crack/damage ® Replace.
Exist fur deposits 3 ® Clean or
replace.

3 - 8
INSP
ADJRADIATOR CAP OPENING PRESSURE INSPECTION/
COOLING SYSTEM INSPECTION
EC356001
RADIATOR CAP OPENING PRESSURE
INSPECTION
1. Attach:
lRadiator cap tester 1 and adapter 2
NOTE:
Apply water on the radiator cap seal.
3Radiator cap
2. Apply the specified pressure.
3. Inspect:
lPressure
Impossible to maintain the specified
pressure for 10 seconds ® Replace.
Radiator cap tester:
YU-24460-1/90890-01325
Adapter:
YU-33984/90890-01352
Radiator cap opening pressure:
110 kPa (1.1 kg/cm2, 15.6 psi)
EC357002
COOLING SYSTEM INSPECTION
1. Inspect:
lCoolant level
2. Attach:
lRadiator cap tester 1 and adapter 2
3. Apply the specified pressure.
Radiator cap tester:
YU-24460-1/90890-01325
Adapter:
YU-33984/90890-01352
Standard pressure:
180 kPa (1.8 kg/cm2, 25.6 psi)

3 - 9
INSP
ADJ
CLUTCH ADJUSTMENT
NOTE:
lDo not apply pressure more than specified
pressure.
lRadiator should be filled fully.
4. Inspect:
lPressure
Impossible to maintain the specified
pressure for 10 seconds ® Repair.
lRadiator
lRadiator hose joint
Coolant leakage ® Repair or replace.
lRadiator hose
Swelling ® Replace.
EC359020
CLUTCH ADJUSTMENT
1. Check:
lClutch lever free play a
Out of specification ® Adjust.
Clutch lever free play a:
2 ~ 4 mm (0.08 ~ 0.16 in)
2. Adjust:
lClutch lever free play
NOTE:
lMake minute adjustment on the lever side
using the adjuster 3.
lAfter adjustment, check proper operation of
clutch lever. Clutch lever free play adjustment steps:
lLoosen the locknut 1.
lTurn the adjuster 2 until free play a is
within the specified limits.
lTighten the locknut.

3 - 18
INSP
ADJIDLE SPEED ADJUSTMENT/
VALVE CLEARANCE ADJUSTMENT
EC35M021
IDLE SPEED ADJUSTMENT
1. Start the engine and thoroughly warm it
up.
2. Adjust:
lIdle speed
VALVE CLEARANCE ADJUSTMENT
NOTE:
lThe valve clearance should be adjusted
when the engine is cool to the touch.
lThe piston must be at Top Dead Center
(T.D.C.) on compression stroke to check or
adjust the valve clearance.
1. Remove:
lSeat
lSide covers
lAir scoops
lFuel tank
Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section in the CHAPTER 4.
2. Drain:
lCoolant
Refer to “COOLANT REPLACEMENT”
section.
3. Remove:
lRADIATOR
Refer to “RADIATOR” section in the
CHAPTER 4.
lEngine stay (upper)
lCylinder head breather hose
lCylinder head cover
lSpark plug cap
Refer to “CYLINDER HEAD COVER”
section in the CHAPTER 4. Adjustment steps:
lAdjust the pilot screw.
Refer to “PILOT SCREW ADJUSTMENT”
section.
lTurn the throttle stop screw 1 until the
engine runs at the lowest possible speed.
To increase idle speed ®
Turn the throttle stop screw 1 in a.
To decrease idle speed ®
Turn the throttle stop screw 1 out b.
Engine idling speed:
1,700 ~ 1,900 r/min

ENG

4 - 4
RADIATOR
EC450001
RADIATOR
Extent of removal:
1
Radiator removal
Extent of removal Order Part name Q’ty Remarks
RADIATOR REMOVAL
Preparation for removal Drain the coolant. Refer to “COOLANT REPLACEMENT”
section in the CHAPTER 3.
Seat and fuel tank Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section.
Exhaust pipe Refer to “EXHAUST PIPE AND
SILENCER” section.
1 Engine guard 1
2 Panel 2
3 Clamp 8
4 Radiator (right) 1
5 Hose 2 1
6 Hose 3 1
7 Hose 4 1
8 Pipe 2/O-ring 1/1
9 Radiator breather hose 1
10 Radiator (left) 1
11 Hose 1 1
12 Pipe 1/O-ring 1/1
1

ENG
4 - 47
OIL FILTER, WATER PUMP AND CRANKCASE COVER
(RIGHT)
OIL FILTER, WATER PUMP AND CRANKCASE COVER (RIGHT)
OIL FILTER, WATER PUMP AND CRANKCASE COVER (RIGHT)
Extent of removal:1 Oil filter removal2 Water pump removal
3 Crankcase (right) removal
Extent of removal Order Part name Q’ty Remarks
OIL FILTER, WATER PUMP
AND CRANKCASE COVER
(RIGHT) REMOVAL
Preparation for removal Drain the engine oil. Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.
Drain the coolant. Refer to “COOLANT REPLACEMENT”
section in the CHAPTER 3.
Exhaust pipe Refer to “EXHAUST PIPE AND
SILENCER” section in the CHAPTER 3.
Brake pedal Refer to “ENGINE REMOVAL” section.
Clutch cover Refer to “CLUTCH” section.
1 Oil filter cover 1
Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.
2 Oil filter 1
3 Coolant pipe 2 1
4 Water pump housing 1
5 Pin 2
6 Oil delivery pipe 1
1
23

4 - 49
ENG
OIL FILTER, WATER PUMP AND CRANKCASE COVER
(RIGHT)
EC4G3000
REMOVAL POINTS
EC4G3110
Impeller shaft
1. Remove:
lImpeller 1
lPlain washer 2
lImpeller shaft 3
NOTE:
Hold the impeller shaft on its width across the
flats a with spanners, etc. and remove the
impeller.
EC4G3210
Oil seal
NOTE:
It is not necessary to disassemble the water
pump, unless there is an abnormality such as
excessive change in coolant level, discolora-
tion of coolant, or milky transmission oil.
1. Remove:
lBearing 1
2. Remove:
lOil seal 1
EC4G4000
INSPECTION
EC444200
Impeller shaft
1. Inspect:
lImpeller shaft 1
Bend/wear/damage ® Replace.
Fur deposits ® Clean.

4 - 52
ENG
OIL FILTER, WATER PUMP AND CRANKCASE COVER
(RIGHT)
Kick crank
1. Install:
lKick crank 1
NOTE:
Install the kick crank so that the kick crank is
as vertical as possible with the distance a
between the kick crank and the frame being
5 mm (0.20 in) or more.
T R..33 Nm (3.3 m · kg, 24 ft · lb)
2. Install:
lOil hose 1
lBolt (oil hose) 2
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
3. Install:
lCopper washer 1
lOil delivery pipe 2
lUnion bolt (M8) 3
lUnion bolt (M10) 4
T R..18 Nm (1.8 m · kg, 13 ft · lb)
T R..20 Nm (2.0 m · kg, 14 ft · lb)
Water pump housing
1. Install:
lPin 1
lO-ring 2 New
2. Install:
lWater pump housing 1
lBolt (water pump housing) 2
lPlain washer 3
lCoolant drain bolt 4
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
New
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)