2001 YAMAHA WR 426F radiator cap

3 - 5
INSP
ADJ

EC350000
ENGINE
COOLANT LEVEL INSPECTION
WARNING

Do not remove the radiator cap
1
, drain
bolt and hoses when the engine and radia-
tor are hot. Scalding hot fluid and steam
may be blown out under pressure, which
could cause serious injury.
When the engine has cooled, place a thick
towel over the radiator cap, slowly rotate
the cap counterclockwise to the detent.
This procedure allows any residual pres-
sure to escape. When the hissing sound
has stopped, press down on the cap while
turning counterclockwise and remove it.
CAUTION:

Hard water or salt water is harmful to the
engine parts. You may use distilled water, if
you can’t get soft water.
1. Place the machine on a level place, and
hold it in an upright position.
2. Inspect:
l
Coolant level
Coolant level should be between the
maximum
a
and minimum
b
marks.
Coolant level is below the “LOW” level
line
®
Add soft water (tap water) up to
the proper level.
3. Start the engine and let it warm up for
several minutes.
4. Turn off the engine and check the coolant
level again.
NOTE:

Before checking the coolant level, wait a few
minutes until the coolant settles.
LOWFULLCOOLANT
a
b

COOLANT REPLACEMENT
WARNING

Do not remove the radiator cap when the
engine is hot.
ENGINE/COOLANT LEVEL INSPECTION/
COOLANT REPLACEMENT

3 - 6
INSP
ADJ

COOLANT REPLACEMENT
CAUTION:

Take care so that coolant does not splash
on painted surfaces. If it splashes, wash it
away with water.
1. Place a container under the engine.
2. Remove:
l
Seat
Refer to ”SEAT FUEL TANK AND SIDE
COVERS” section in the CHAPTER 4.
3. Disconnect:
l
Coolant reservoir hose
1

Drain the coolant completely.
4. Connect:
l
Coolant reservoir hose
LOWFULLCOOLANT1

5. Remove:
l
Engine guard
1

l
Coolant drain bolt
2

6. Remove:
l
Radiator cap
Drain the coolant completely.
7. Clean:
l
Cooling system
Thoroughly flush the cooling system
with clean tap water.
8. Install:
l
Copper washer
l
Coolant drain bolt
l
Engine guard
l
Bolt [engine guard (front)]
l
Bolt [engine guard (rear)]
New
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..34 Nm (3.4 m · kg, 24 ft · lb)
T R..23 Nm (2.3 m · kg, 17 ft · lb)

3 - 7
INSP
ADJ
COOLANT REPLACEMENT
9. Fill:
lRadiator
lEngine
To specified level.
CAUTION:
lDo not mix more than one type of ethyl-
ene glycol antifreeze containing corro-
sion inhibitors for aluminum engine.
lDo not use water containing impurities or oil.
Recommended coolant:
High quality ethylene glycol
anti-freeze containing
anti-corrosion for
aluminum engine
Coolant 1 and water
(soft water) 2 mixing ratio:
50%/50%
Coolant capacity:
1.2 L (1.06 Imp qt, 1.27 US qt)
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.
10. Install:
lRadiator cap
11. Fill:
lCoolant reservoir tank
Midway a between maximum and min-
imum marks on the tank.
LOWFULLCOOLANTa

3 - 8
INSP
ADJRADIATOR CAP INSPECTION/
RADIATOR CAP OPENING PRESSURE INSPECTION
12. Install:
lCoolant reservoir cap
13. Start the engine and let it warm up for
several minutes.
14. Turn off the engine and inspect the cool-
ant level.
Refer to “COOLANT LEVEL INSPEC-
TION” section.
NOTE:
Before checking the coolant level wait a few
minutes until the coolant settles.
RADIATOR CAP INSPECTION
1. Inspect:
lSeal (radiator cap) 1
lValve and valve seat 2
Crack/damage ® Replace.
Fur deposits 3 ® Clean or replace.
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.
Radiator cap tester:
YU-24460-01/90890-01325
Adapter:
YU-33984/90890-01352
Radiator cap opening pressure:
110 kPa (1.1 kg/cm2, 15.6 psi)

3 - 9
INSP
ADJ
COOLING SYSTEM INSPECTION
3. Inspect:
lPressure
Impossible to maintain the specified
pressure for 10 seconds ® Replace.
EC357002
COOLING SYSTEM INSPECTION
1. Inspect:
lCoolant level
2. Attach:
lRadiator cap tester 1 and adapter 2
3. Apply the specified pressure.
NOTE:
lDo not apply pressure more than specified
pressure.
lRadiator should be filled fully.
Radiator cap tester:
YU-24460-01/90890-01325
Adapter:
YU-33984/90890-01352
Standard pressure:
180 kPa (1.8 kg/cm2, 25.6 psi)
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.

4 - 6
ENG

RADIATOR
EC456000
HANDLING NOTE
WARNING

Do not remove the radiator cap when the
engine and radiator are hot. Scalding hot
fluid and steam may be blown out under
pressure, which could cause serious
injury.
When the engine has cooled, open the radi-
ator cap by the following procedure:
Place a thick rag, like a towel, over the radi-
ator cap, slowly rotate the cap counter-
clockwise to the detent. This procedure
allows any residual pressure to escape.
When the hissing sound has stopped,
press down on the cap while turning coun-
terclockwise and remove it.
EC454000
INSPECTION
EC444100
Radiator
1. Inspect:
l
Radiator core
1

Obstruction
®
Blow out with com-
pressed air through rear of the radiator.
Bent fin
®
Repair/replace.
EC455000
ASSEMBLY AND INSTALLATION
Radiator
1. Install:
l
Pipe 1
1
lHose 1 2
lPipe 2 3
lHose 3 4
lHose 4 5
2. Install:
lHose 2 1
lRadiator (left) 2
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

ENG
4 - 87
ENGINE REMOVAL
EC4M0000
ENGINE REMOVAL
Extent of removal Order Part name Q’ty Remarks
ENGINE REMOVAL
Preparation for removal Hold the machine by placing the
suitable stand under the frame.
WARNING
Support the machine securely so there is nodanger of it falling over.
Seat and fuel tank Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section.
Carburetor Refer to “CARBURETOR” section.
Exhaust pipe and silencer Refer to “EXHAUST PIPE AND
SILENCER” section.
Clutch cable Disconnect at engine side.
Decompression cable and guide Disconnect at engine side.
Radiator Refer to “RADIATOR” section.
Shift pedal Refer to “CDI MAGNETO” section.
Cylinder head breather hose and
oil tank breather hoseRefer to “CAMSHAFTS” section.
Drain the engine oil Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.
Spark plug cap
Disconnect the CDI magneto lead.