2002 YAMAHA WR 426F radiator

2 - 33
SPECMAINTENANCE SPECIFICATIONS (WR400F)
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
Rear wheel axle and nut M20 × 1.5 1 125 12.5 90
Driven sprocket and wheel hub M8 × 1.25 6 42 4.2 30
Nipple (spoke)—72 3 0.3 2.2
Disc cover and rear brake caliper M6 × 1.0 2 7 0.7 5.1
Protector and rear brake caliper M6 × 1.0 2 7 0.7 5.1
Engine mounting:
Engine bracket and frame M8 × 1.25 7 34 3.4 24
Engine and frame (front) M10 × 1.25 1 69 6.9 50
Engine and frame (upper) M10 × 1.25 1 55 5.5 40
Engine and frame (lower) M10 × 1.25 1 69 6.9 50
Engine guard (left and right) M8 × 1.25 2 23 2.3 17
Pivot shaft and nut M16 × 1.5 1 85 8.5 61
Relay arm and swingarm M14 × 1.5 1 80 8.0 58
Relay arm and connecting rod M14 × 1.5 1 80 8.0 58
Connecting rod and frame M14 × 1.5 1 80 8.0 58
Rear shock absorber and frame M10 × 1.25 1 56 5.6 40
Rear shock absorber and relay arm M10 × 1.25 1 53 5.3 38
Rear frame and frame M8 × 1.25 3 29 2.9 21
Swingarm and brake hose holder M5 × 0.8 4 1 0.1 0.7
Swingarm and patch M4 × 0.7 4 2 0.2 1.4
Drive chain tensioner mounting (upper) M8 × 1.25 1 19 1.9 13
Drive chain tensioner mounting (lower) M8 × 1.25 1 20 2.0 14
Chain support and swingarm M6 × 1.0 3 7 0.7 5.1
Seal guard and swingarm M5 × 0.8 4 6 0.6 4.3
Fuel tank mounting M6 × 1.0 2 10 1.0 7.2
Fuel tank and fuel cock M6 × 1.0 2 7 0.7 5.1
Fuel tank and seat set bracket M6 × 1.0 1 7 0.7 5.1
Fuel tank and hooking screw (fitting band) M6 × 1.0 1 7 0.7 5.1
Fuel tank and fuel tank bracket M6 × 1.0 4 7 0.7 5.1
Seat mounting M8 × 1.25 2 23 2.3 17
Side cover mounting M6 × 1.0 2 7 0.7 5.1
Air scoop and fuel tank M6 × 1.0 4 4 0.4 2.9
Air scoop and radiator panel (lower) M6 × 1.0 2 4 0.4 2.9
Front fender mounting M6 × 1.0 4 7 0.7 5.1
Rear fender and air filter case M6 × 1.0 2 7 0.7 5.1
Rear fender and frame (right) M6 × 1.0 1 10 1.0 7.2
Headlight stay (lower) and under bracket M8 × 1.25 2 7 0.7 5.1
Headlight (left and right) M6 × 1.0 2 10 1.0 7.2
Headlight (lower) M6 × 1.0 1 7 0.7 5.1
Tail light M6 × 1.0 3 4 0.4 2.9
Tail light lead clamp and rear fender M4 × 1.59 2 1 0.1 0.7
Coolant reservoir tank (front) M6 × 1.0 1 7 0.7 5.1
Coolant reservoir tank (rear) M6 × 1.0 1 11 1.1 8.0
Sidestand bracket and frame M10 × 1.25 2 66 6.6 48
Sidestand mounting M10 × 1.25 1 64 6.4 46

2 - 39
SPECCABLE ROUTING DIAGRAM
ÈMake sure that the TPS read
coupler does not go outside
the chassis.
ÔFasten the TPS lead under the
coupler to the frame with a
plastic locking tie.
Pass the carburetor breather
hoses and overflow hose
between the connecting rod
and cross tube (frame).
ÒFasten the neutral switch lead
and oil hose together with a
plastic locking tie and cut off
the tie end.
˜Fasten the cylinder head
breather hose with the hose
holder.
ˆFasten the neutral switch lead
to the frame with a plastic
band ends toward the rear of
the frame.ØFasten the neutral switch lead
and CDI magneto lead
together with a plastic band.
∏Pass the clutch cable through
the cable guide.
ŒPass the cylinder head
breather hose along the inner
side of the radiator pipe.
ÂPass the clutch cable between
the frame and radiator and
over the lower boss on the
radiator.
ÍPass the neutral switch lead
and CDI magneto lead through
the cable guide and over the
middle radiator mounting boss.
Then, pass the decompression
cable under the middle radia-
tor mounting boss and along
the left side of the neutral
switch lead and CDI magneto
lead.ÊPass the clutch cable through
the cable guide.
ËFit the brake hose into the
guides on the protector.
◊Fasten the ignition coil lead
(in the sub wire harness) on
the upper inside of the frame
and cut off the tie end.
„Pass the ignition coil lead (in
the sub wire harness) under
the cushion bracket (frame).
≈Fasten the ignition coil lead
(in the sub wire harness) to
the frame with a plastic lock-
ing tie and cut off the tie end.
ÁPass the carburetor breather
hoses, overflow hose and
coolant reservoir tank
breather hose so that all there
hoses do not contact the rear
shock absorber.

2 - 40
SPECCABLE ROUTING DIAGRAM
1Coolant reservoir tank
breather hose
2Clamp
3Ignition coil
4High tension cord
5CDI unit
6CDI unit band
7“ENGINE STOP” button
lead
8Throttle cable (pull)
9Throttle cable (return)
0Radiator (left)
ARadiator (right)
BDecompression cable
CCDI unit stay (frame)ÅFasten the coolant reservoir tank
breather hose and carburetor
breather hoses together with a
plastic locking tie.
ıFasten the ignition coil lead to the
frame with a plastic band.
ÇPass the ignition coil lead (in the
sub wire harness) so that it does
not contact the carburetor and
rear shock absorber and connect
it with the lead from the ignition
coil on the inside of the frame.
ÎFasten the ignition coil and
ground lead to the frame with the
bolt.
‰Pass the throttle cables over the
high tension cord.
ÏPass the throttle cables along the
outer side of the CDI unit leads.ÌFasten the CDI unit leads and
“ENGINE STOP” button lead to
the frame at the protector of the
CDI unit leads with a plastic lock-
ing tie.
ÓFit the boot over the coupler.
ÈPass the throttle cables between
the top radiator mounting boss
and middle radiator mounting
boss.
ÔPass the CDI unit lead and
“ENGINE STOP” button lead over
the top radiator mounting boss.
Pass the throttle cables and
“ENGINE STOP” button lead
through the cable guide.
ÒCross the pull and return throttle
cables before the radiator.
˜Insert the CDI unit band over the
CDI unit stay (frame) as far as
possible.

3 - 2
INSP
ADJ
MAINTENANCE INTERVALS
SHIFT FORK, SHIFT CAM, GUIDE BAR
Inspect
●Inspect wear
ROTOR NUT
Retighten
●●
MUFFLER
Inspect and retighten
Clean
Replace
●●
●
●
*Whichever comes first
*SPARK ARRESTER
Clean
(Every
six
months)
●
CRANK
Inspect and clean
●●
CARBURETOR
Inspect, adjust and clean
●●
When using a high-pres-
sure washer, make sure
that water does not enter
the accelerator pump.
SPARK PLUG
Inspect and clean
Replace
●●
●
DRIVE CHAIN
Lubricate, slack, alignment
Replace
●●
●
Use chain lube
Chain slack: 40 ~ 50 mm
(1.6 ~ 2.0 in)
COOLING SYSTEM
Check coolant level and leakage
Check radiator cap operation
Replace coolant
Inspect hoses
●●
●●
●
Every two years
OUTSIDE NUTS AND BOLTS
Retighten
●●
Refer to “STARTING AND
BREAK-IN” section in the
CHAPTER 1.
AIR FILTER
Clean and lubricate
Replace
●●
●Use foam air-filter oil
OIL STRAINER (frame)
Clean
●
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 ItemAfter
break-inEvery
race
Every
third
or
500 km
(300 mi)Every
fifth
or
1,000 km
(600 mi)
As 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 filler cap.
Check that the coolant level is correct in the coolant reservoir
tank.
Check the cooling system for leakage.P.3-5 ~ 9
FuelCheck that a fresh gasoline is filled in the fuel tank. Check the
fuel line for leakage.P.1-14
Engine oilCheck that the oil level is correct. Check the crankcase and
frame oil line for leakage.P.3-14 ~ 18
Gear shifter and clutchCheck that gears can be shifted correctly in order and that the
clutch operates smoothly.P.3-10
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 ~ 11
Brakes Check the play of front brake and effect of front and rear brake. P.3-26 ~ 32
ChainCheck chain slack and alignment. Check that the chain is lubri-
cated properly.P.3-33 ~ 36
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P.3-44 ~ 45
SteeringCheck that the handlebar can be turned smoothly and have no
excessive play.P.3-45 ~ 46
Front forks and rear shock
absorberCheck that they operate smoothly and there is no oil leakage. P.3-36 ~ 43
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.—
Muffler Check that the muffler is tightly mounted and has no cracks.—
Sprocket Check that the driven sprocket tightening bolt is not loose. P.3-33
Lubrication Check for smooth operation. Lubricate if necessary. P.3-47
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P.1-19
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 ~ 22

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:
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:
Seat
Refer to ”SEAT FUEL TANK AND SIDE
COVERS” section in the CHAPTER 4.
3. Disconnect:
Coolant reservoir hose 1
Drain the coolant completely.
4. Connect:
Coolant reservoir hose
LOWFULLCOOLANT1
5. Remove:
Engine guard 1
Coolant drain bolt 2
6. Remove:
Radiator cap
Drain the coolant completely.
7. Clean:
Cooling system
Thoroughly flush the cooling system
with clean tap water.
8. Install:
Copper washer
Coolant drain bolt
Engine guard
Bolt [engine guard (front)]
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:
Radiator
Engine
To specified level.
CAUTION:
Do not mix more than one type of ethyl-
ene glycol antifreeze containing corro-
sion inhibitors for aluminum engine.
Do 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
When coolant splashes to your eye.
Thoroughly wash your eye with water
and see your doctor.
When coolant splashes to your clothes.
Quickly wash it away with water and
then with soap.
When coolant is swallowed.
Quickly make him vomit and take him
to a doctor.
10. Install:
Radiator cap
11. Fill:
Coolant reservoir tank
Midway a between maximum and min-
imum marks on the tank.
LOWFULLCOOLANTa