2001 YAMAHA YZ426F radiator

2 - 24
SPECCABLE ROUTING DIAGRAM
1Clamp
2Ignition coil
3High tension cord
4CDI unit
5CDI unit band
6Throttle cable (pull)
7Throttle cable (return)
8Radiator (left)
9Radiator breather hose
0Radiator (right)
ACDI unit stay (frame)Fasten the ignition coil lead to the
frame with a plastic band.
õFasten the ignition coil and ground
lead to the frame with the bolt.
‚Pass 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.
ëPass the throttle cables over the
high tension cord.
äPass the throttle cables along the
outer side of the CDI unit leads.
ìUsing a plastic locking tie, clamp
to the frame the CDI unit leads at
their protecting tubes.íPass the throttle cables between
the top radiator mounting boss
and middle radiator mounting
boss.
îPass the CDI unit leads over the
top radiator mounting boss.
éCross the pull and return throttle
cables before the radiator.
ïPass the throttle cables through
the cable guide.
ðPass the radiator breather hose
between the frame and the radia-
tor without pinching it.
ñPass the radiator breather hose
behind the decompression cable.
÷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
c
Inspect wear
ROTOR NUT
Retighten
c

c

MUFFLER
Inspect and retighten
Clean
Replace
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c

c
* Whichever comes first
CRANK
Inspect and clean
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CARBURETOR
Inspect, adjust and clean
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c
When using a high-pres-
sure washer, make sure
that water does not enter
the accelerator pump.
SPARK PLUG
Inspect and clean
Replace
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DRIVE CHAIN
Lubricate, slack, alignment
Replace
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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
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Every two years
OUTSIDE NUTS AND BOLTS
Retighten
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Refer to “STARTING
AND BREAK-IN” section
in the CHAPTER 1.
AIR FILTER
Clean and lubricate
Replace
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Use foam air-filter oil
OIL STRAINER (frame)
Clean
c

FRAME
Clean and inspect
c

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FUEL TANK, COCK
Clean and inspect
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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
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Every one year
FRONT FORKS
Inspect and adjust
Replace oil
Replace oil seal
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Suspension oil “01”
FRONT FORK OIL SEAL AND DUST
SEAL
Clean and lube
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Lithium base grease ItemAfter
break-inEvery
race
Every
third
(or
500 km)Every
fifth
(or
1,000 km)
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 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.1-13 ~ 14
Engine oilCheck that the oil level is correct. Check the crankcase and
frame oil line for leakage.P.3-13 ~ 17
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 ~ 11
Brakes Check the play of front brake and effect of front and rear brake. P.3-24 ~ 30
ChainCheck chain slack and alignment. Check that the chain is lubri-
cated properly.P.3-31 ~ 33
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P.3-41 ~ 42
SteeringCheck that the handlebar can be turned smoothly and have no
excessive play.P.3-42 ~ 43
Front forks and rear shock
absorberCheck that they operate smoothly and there is no oil leakage. P.3-33 ~ 40
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.3-31
Lubrication Check for smooth operation. Lubricate if necessary. P.3-44
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P.1-18
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 ~ 21

3 - 5
INSP
ADJ
EC350000
ENGINE
EC351011
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. Remove:
lRadiator cap
3. Check:
lCoolant level a
Coolant level low ® Add coolant.
1Radiator
ENGINE/COOLANT LEVEL INSPECTION

3 - 6
INSP
ADJ
COOLANT REPLACEMENT
EC353011
COOLANT REPLACEMENT
WARNING
Do not remove the radiator cap when the
engine is hot.
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:
lEngine guard 1
lCoolant drain bolt 2
3. Remove:
lRadiator cap
Drain the coolant completely.
4. Clean:
lCooling system
Thoroughly flush the cooling system
with clean tap water.
5. Install:
lCopper washer
lCoolant drain bolt
lEngine guard
lBolt [engine guard (front)]
lBolt [engine guard (rear)]
6. Fill:
lRadiator
lEngine
To specified level.
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)
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
RADIATOR CAP INSPECTION
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.
7. Install:
lRadiator 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-24460-01/90890-01325
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-24460-01/90890-01325
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 2.
lAfter adjustment, check proper operation of
clutch lever. Clutch lever free play adjustment steps:
lLoosen the locknuts 1.
lAdjust the free play by changing their
tightening position.
lTighten the locknuts.