2000 YAMAHA YZ426F oil

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INSP
ADJ
AIR FILTER CLEANING
EC35G040
AIR FILTER CLEANING
NOTE:
Proper air filter maintenance is the biggest key
to preventing premature engine wear and
damage.
CAUTION:
Never run the engine without the air filter
element in place; this would allow dirt and
dust to enter the engine and cause rapid
wear and possible engine damage.
1. Remove:
lSeat
lFitting bolt 1
lWasher 2
lAir filter element 3
lFilter guide 4
2. Clean:
lAir filter element
Clean them with solvent.
NOTE:
After cleaning, remove the remaining solvent
by squeezing the element.
CAUTION:
lDo not twist the element when squeezing
the element.
lLeaving too much of solvent in the ele-
ment may result in poor starting.
3. Inspect:
lAir filter element
Damage ® Replace.
4. Apply:
lFoam-air-filter oil or engine oil to the ele-
ment.
NOTE:
Squeeze out the excess oil. Element should
be wet but not dripping.
5. Install:
lFilter guide 1
NOTE:
Align the projection a on filter guide with the
hole b in air filter element.

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ENGINE OIL LEVEL INSPECTION
6. Apply:
lLithium soap base grease
On the matching surface a on air filter
element.
7. Install:
lAir filter element 1
lWasher
lFitting bolt
NOTE:
Align the projection a on filter guide with the
hole b in air filter case.
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
ENGINE OIL LEVEL INSPECTION
1. Stand the motorcycle on a level surface.
NOTE:
lWhen checking the oil level make sure that
the motorcycle is upright.
lPlace the motorcycle on a suitable stand.
WARNING
Never remove the oil tank cap just after
high speed operation. The heated oil could
spurt out. causing danger. Wait until the oil
cools down to approximately 70 ˚C (158 ˚F).
2. Idle the engine more than 3 minutes
while keeping the motorcycle upright.
Then stop the engine and inspect the oil
level.
3. Remove:
lOil tank cap 1

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INSP
ADJ
4. Inspect:
lOil level
Oil level should be between maximum
a and minimum b marks.
Oil level low ® Add oil to proper level.
NOTE:
When inspecting the oil level, do not screw the
oil level gauge into the oil tank.
Insert the gauge lightly.
(For USA and CDN)
CAUTION:
lDo not add any chemical additives.
Engine oil also lubricates the clutch and
additives could cause clutch slippage.
lDo not allow foreign material to enter the
crankcase.
(Except for USA and CDN)
CAUTION:
lDo not add any chemical additives or use
oils with a grade of CD a or higher.
lDo not use oils labeled “ENERGY CON-
SERVING II” b or higher. Engine oil also
lubricates the clutch and additives could
cause clutch slippage.
lDo not allow foreign materials to enter the
crankcase.
Recommended oil:
At 5 ˚C (40 ˚F) or higher
Yamalube 4 (20W40) or SAE
20W40 type SH motor oil
(Non-Friction modified)
At 15 ˚C (60 ˚F) or lower õ
Yamalube 4 (10W30) or SAE
10W30 type SH motor oil
(Non-Friction modified)
and/or
Yamalube 4-R (15W50)
(Non-Friction modified)
Recommended oil:
Refer to the following chart for
selection of oils which are suited
to the atmospheric temperatures.
Recommended engine oil classi-
fication:
API STANDARD:
API “SH” or higher grade
(Designed primarily for motor-
cycles)-20
-4-10
140
3010
5020
6830
8640 50
104
122¡CTemp.
¡F
10W/30
10W/40
20W/40
20W/50
a
b
ENGINE OIL LEVEL INSPECTION

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INSP
ADJ
ENGINE OIL REPLACEMENT
5. Start the engine and let it warm up for
several minutes.
CAUTION:
When the oil tank is empty, never start the
engine.
6. Idle the engine more than 10 seconds
while keeping the motorcycle upright.
Then stop the engine and add the oil to
the maximum level.
7. Install:
lOil tank cap
ENGINE OIL REPLACEMENT
1. Start the engine and let it warm up for
several minutes.
2. Stop the engine and place an oil pan
under the drain bolt.
3. Remove:
lOil filler plug 1
lDrain bolt (with gasket) 2
lDrain bolt (with gasket) 3
lOil filter drain bolt (O-ring) 4
Drain the crankcase and oil tank
(frame) of its oil.
4. Remove:
lEngine skidplate
lEngine oil hose clamp 1
lEngine oil hose 2
lOil strainer (frame) 3
5. Clean:
lOil strainer (frame)

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INSP
ADJ
ENGINE OIL REPLACEMENT
6. If the oil filter is to be replaced during this
oil change, remove the following parts
and reinstall them.
7. Install:
lOil strainer (frame) 1
lPlain washer 2
lEngine oil hose 3
lEngine oil hose clamp 4
lEngine skid plate
8. Install:
lGaskets
lOil filter drain bolt
lDrain bolt (crankcase)
lDrain bolt (frame) Replacement steps:
lRemove the exhaust pipe.
lRemove the oil filter cover 1 and oil filter
element 2.
lCheck the O-rings 3, if cracked or dam-
aged, replace them with a new one.
lInstall the oil filter element and oil filter
cover.
T R..
Oil filter cover:
10 Nm (1.0 m • kg, 7.2 ft • lb)
T R..90 Nm (9.0 m · kg, 65 ft · lb)
New
New
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..20 Nm (2.0 m · kg, 14 ft · lb)
T R..23 Nm (2.3 m · kg, 17 ft · lb)
9. Fill:
lOil tank (frame)
10. Install:
lOil filler plug
11. Inspect:
lEngine (for oil leaks)
lOil level
Refer to “ENGINE OIL LEVEL INSPEC-
TION”.
Oil quantity:
Total amount:
1.7 L (1.50 Imp qt, 1.80 US qt)
Periodic oil change:
1.5 L (1.32 Imp qt, 1.59 US qt)
With oil filter replacement:
1.6 L (1.41 Imp qt, 1.69 US qt)

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ADJ
PILOT SCREW ADJUSTMENT
12. Check:
lOil pressure
Checking steps:
lSlightly loosen the oil gallery bolt 1.
lStart the engine and keep it idling until oil
starts to seep from the oil gallery bolt. If no
oil comes out after one minute, turn the
engine off so it will not seize.
lCheck oil passages, oil filter and oil pump
for damage or leakage.
lStart the engine after solving the prob-
lem(s) and recheck the oil pressure.
lTighten the oil gallery bolt to specification.
T R..
Oil gallery bolt:
18 Nm (1.8 m • kg, 13 ft • lb)
PILOT SCREW ADJUSTMENT
1. Adjust:
lPilot screw 1
* Except for USAAdjusting steps:
lTurn in the pilot screw until it is lightly
seated.
lTurn out the pilot screw by the factory-set
number of turns.
Pilot screw:
1-3/4 turns out
* 1-1/2 turns out
(for reference only)
NOTE:
To optimize the fuel flow at a smaller throt-
tle opening, each machine’s pilot screw has
been individually set at the factory. Before
adjusting the pilot screw, turn it in fully and
count the number of turns. Record this
number as the factory-set number of turns
out.

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INSP
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VALVE CLEARANCE ADJUSTMENT
lRound off the last digit of the installed pad
number to the nearest increment.
Last digit of pad
numberRounded value
0 or 2 0
5(NOT ROUNDED
OFF)
810
EXAMPLE:
Installed pad number = 148
Rounded off value = 150
lLocate the rounded-off value and the
measured valve clearance in the chart
“PAD SELECTION TABLE”. The field
where these two coordinates intersect
shows the new pad number to use.
lInstall the new pads 0 and the valve lift-
ers A.
lInstall the camshafts (exhaust and intake),
the timing chain and the camshaft caps.
T R..
Bolt (camshaft cap)
7 Nm (0.7 m • kg, 5.1 ft • lb)
NOTE:
Pads can only be selected in 0.05 mm
increments.
NOTE:
Use the new pad number only as a guide
when verifying the valve clearance adjust-
ment.
NOTE:
lLubricate the valve lifters and pads with
molybdenum disulfide oil.
lValve lifter must turn smoothly when
rotated with a finger.
lBe careful to reinstall valve lifters and
pads in their original place.

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SPROCKETS INSPECTION/DRIVE CHAIN INSPECTION
EC368000
SPROCKETS INSPECTION
1. Inspect:
lSprocket teeth a
Excessive wear ® Replace.
NOTE:
Replace the drive, driven sprockets and drive
chain as a set.
EC369002
DRIVE CHAIN INSPECTION
1. Remove:
lMaster link clip
lJoint 1
lDrive chain 2
2. Clean:
lDrive chain
Place it in kerosene, and brush off as
much dirt as possible. Then remove the
chain from the kerosene and dry the
chain.
3. Measure:
lDrive chain length (10 links) a
Out of specification ® Replace.
Drive chain length (10 links):
Limit: 152.5 mm (6.00 in)
4. Check:
lDrive chain stiffness
Clean and oil the chain and hold as
illustrated.
Stiff ® Replace drive chain.