engine YAMAHA WR 450F 2007 Service Manual

3 - 10
INSP
ADJ
THROTTLE CABLE ADJUSTMENT
2. Adjust:
Clutch lever free play
NOTE:
Make minute adjustment on the lever side
using the adjuster 3.
After adjustment, check proper operation of
clutch lever. Clutch lever free play adjustment steps:
Loosen the locknut 1.
Turn the adjuster 2 until free play a is
within the specified limits.
Tighten the locknut.
T R..
Locknut:
4 Nm (0.4 m · kg, 2.9 ft · lb)
EC35A001
THROTTLE CABLE ADJUSTMENT
1. Check:
Throttle grip free play a
Out of specification → Adjust.
2. Adjust:
Throttle grip free play
Throttle grip free play
a:
3 ~ 5 mm (0.12 ~ 0.20 in)
Throttle grip free play adjustment steps:
Slide the adjuster cover.
Loosen the locknut 1.
Turn the adjuster 2 until the specified free
play is obtained.
Tighten the locknut.
T R..
Locknut:
4 Nm (0.4 m  kg, 2.9 ft  lb)
NOTE:
Before adjusting the throttle cable free play,
the engine idle speed should be adjusted.
WARNING
After adjusting the throttle cable free
play, start the engine and turn the han-
dlebar to right and left and make sure
that the engine idling does not run faster.
1 2

3 - 12
INSP
ADJ
AIR FILTER CLEANING
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. Open the air filter case cover 1
NOTE:
Loosen the quick screw 2 and pull on it to
open the air filter case cover.
2. Unhook:
Binder 1
3. Remove:
Air filter element 1
Filter guide 2
4. Clean:
Air filter element
Clean them with solvent.
NOTE:
After cleaning, remove the remaining solvent
by squeezing the element.

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CAUTION:
Do not twist the element when squeezing
the element.
Leaving too much of solvent in the ele-
ment may result in poor starting.
5. Inspect:
Air filter element
Damage → Replace.
6. Apply:
Foam-air-filter oil or equivalent oil to the
element.
NOTE:
Squeeze out the excess oil. Element should
be wet but not dripping.
Wipe off the oil left on the element surface
using a clean dry cloth. (Excess oil in the ele-
ment may adversely affect engine starting.)
7. Install:
Filter guide 1
NOTE:
Align the projection a on filter guide with the
hole b in air filter element.
Apply the lithium soap base grease on the
matching surface c on air filter element.
8. Install:
Air filter element 1
NOTE:
Align the projection a on filter guide with the
hole b in air filter case.
9. Hook:
Binder 1
NOTE:
Hook the binder 1 so that it contacts the filter
guide projections a.
AIR FILTER CLEANING

3 - 14
INSP
ADJ
ENGINE OIL LEVEL INSPECTION
ENGINE OIL LEVEL INSPECTION
1. Stand the machine on a level surface.
NOTE:
When checking the oil level make sure that
the machine is upright.
Place the machine 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 machine upright. Then stop the
engine and inspect the oil level.
3. Remove:
Oil tank plug 1
4. Inspect:
Oil level
Check that the engine oil is above the
level mark a and that the oil does not
come out when the check bolt 1 is
removed.
Below the level mark a → Add oil
through the filler cap hole until it is above
the level mark a.
Oil comes out at the check bolt → Drain
the oil until it stops coming out.
NOTE:
When inspecting the oil level, do not screw the
oil level gauge into the oil tank.
Insert the gauge lightly.

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INSP
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ENGINE OIL LEVEL INSPECTION
(For USA and CDN)
CAUTION:
Do not add any chemical additives.
Engine oil also lubricates the clutch and
additives could cause clutch slippage.
Do not allow foreign material to enter the
crankcase.
(Except for USA and CDN)
CAUTION:
Do not add any chemical additives or use
oils with a grade of CD
a or higher.
Do not use oils labeled “ENERGY CON-
SERVING II”
b or higher. Engine oil also
lubricates the clutch and additives could
cause clutch slippage.
Do not allow foreign materials to enter the
crankcase.
5. Start the engine and let it warm up for sev-
eral minutes.
CAUTION:
When the oil tank is empty, never start the
engine.
Recommended oil:
Yamalube 4, SAE10W30 or
SAE20W40
Yamalube 4-R, SAE10W50
API service SG type or higher,
JASO standard MA
Recommended oil:
SAE10W30, SAE10W40,
SAE15W40, SAE20W40 or
SAE20W50
API service SG type or higher,
JASO standard MA
-20 -10 0 10 20 30 40 50
˚C 0 10 30 50 70 90 110 130
˚F
YAMALUBE 4(10W-30) or SAE 10W-30
YAMALUBE 4(20W-40) or SAE 20W-40
YAMALUBE 4-R(10W-50) or SAE 10W-50
-20 -10 0 10 20 30 40 50
˚C
SAE 10W-30
SAE 10W-40
SAE 15W-40
SAE 20W-40
SAE 20W-50
a
b

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ENGINE OIL REPLACEMENT
6. Idle the engine more than 10 seconds
while keeping the machine upright. Then
stop the engine and add the oil to the maxi-
mum level.
7. Install:
Oil tank plug
ENGINE OIL REPLACEMENT
1. Start the engine and let it warm up for sev-
eral minutes.
2. Stop the engine and place an oil pan under
the drain bolt.
3. Remove:
Engine guard 1
Oil tank plug 2
Oil filler cap 3
Drain bolt (with gasket) 4
Oil filter drain bolt (O-ring) 5
Drain bolt (with gasket) 6
Drain the crankcase and oil tank of its oil.

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ENGINE OIL REPLACEMENT
4. If the oil filter is to be replaced during this
oil change, remove the following parts and
reinstall them.
5. Install:
Gaskets
Oil filter drain bolt
Drain bolt (crankcase right)
Drain bolt (crankcase left)
6. Fill:
Crankcase
7. Install:
Oil filler cap 1
8. Inspect:
Engine (for oil leaks)
Oil level
Refer to “ENGINE OIL LEVEL INSPEC-
TION”. Replacement steps:
Remove the oil filter cover 1 and oil filter
element 2.
Check the O-rings 3, if cracked or dam-
aged, replace them with a new one.
Install the oil filter element and oil filter
cover.
T R..
Oil filter cover:
10 Nm (1.0 m  kg, 7.2 ft  lb)
Oil quantity:
Periodic oil change:
0.95 L (0.84 Imp qt, 1.00 US qt)
With oil filter replacement:
1.0 L (0.88 Imp qt, 1.06 US qt)
Total amount:
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..20 Nm (2.0 m · kg, 14 ft · lb)
T R..20 Nm (2.0 m · kg, 14 ft · lb)

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IDLE SPEED ADJUSTMENT
9. Check:
Oil pressure
Checking steps:
Slightly loosen the oil gallery bolt 1.
Start 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.
Check oil passages, oil filter and oil pump
for damage or leakage.
Start the engine after solving the prob-
lem(s) and recheck the oil pressure.
Tighten the oil gallery bolt to specification.
T R..
Oil gallery bolt:
10 Nm (1.0 m  kg, 7.2 ft  lb)
EC35M021
IDLE SPEED ADJUSTMENT
1. Start the engine and thoroughly warm it up.
2. Adjust:
Idle speed
Adjustment steps:
Turn the throttle stop screw 1 until the
specified engine idling speed.
NOTE:
Using a digital engine tachometer for idle
speed adjustment, detect the engine idling
speed by bringing the sensing element c of
the engine tachometer close to the ignition
coil 2.
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:
1,750 ~ 1,850 r/min
c2

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VALVE CLEARANCE ADJUSTMENT
VALVE CLEARANCE ADJUSTMENT
NOTE:
The valve clearance should be adjusted
when the engine is cool to the touch.
The piston must be at Top Dead Center
(T.D.C.) on compression stroke to check or
adjust the valve clearance.
1. Remove:
Seat
Fuel tank
Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section in the CHAPTER 4.
2. Remove:
Air cut-off valve assembly
Refer to “AIR INDUCTION SYSTEM”
section in the CHAPTER 4.
Spark plug
Engine stay (upper)
Cylinder head cover
Refer to “CAMSHAFTS” section in the
CHAPTER 4.
3. Remove:
Timing plug 1
Straight plug 2
O-ring
1
2
4. Check:
Valve clearance
Out of specification → Adjust.
Valve clearance (cold):
Intake valve:
0.10 ~ 0.15 mm
(0.0039 ~ 0.0059 in)
Exhaust valve:
0.20 ~ 0.25 mm
(0.0079 ~ 0.0098 in)
Checking steps:
Turn the crankshaft counterclockwise with
a wrench.
Align the T.D.C. mark a on the rotor with
the align mark b on the crankcase cover
when piston is at T.D.C. on compression
stroke.
b
a

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ADJ
6. Install:
All removed parts
NOTE:
Install all removed parts in reversed order of
their removal.Locate the rounded-off value and the mea-
sured valve clearance in the chart “PAD
SELECTION TABLE”. The field where
these two coordinates intersect shows the
new pad number to use.
NOTE:
Use the new pad number only as a guide
when verifying the valve clearance adjust-
ment.
Install the new pads 6 and the valve lift-
ers 7.
NOTE:
Apply the engine oil on the valve lifters.
Apply the molybdenum disulfide oil on the
valve stem ends.
Valve lifter must turn smoothly when
rotated with a finger.
Be careful to reinstall valve lifters and
pads in their original place.
Install the camshafts (exhaust and intake),
the timing chain and the camshaft caps.
Refer to “CAMSHAFTS” section in the
CHAPTER 4.
T R..
Bolt (camshaft cap):
10 Nm (1.0 m  kg, 7.2 ft  lb)
Install the timing chain tensioner.
Refer to “CAMSHAFTS” section in the
CHAPTER 4.
NOTE:
Turn the crankshaft counterclockwise sev-
eral turns so that the installed parts settle
into the right position.
Recheck the valve clearance.
If the clearance is still incorrect, repeat all
the clearance adjustment steps until the
specified clearance is obtained.
VALVE CLEARANCE ADJUSTMENT