Yamaha Wr 450 F Owners Manual

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INSP
ADJ
ENGINE OIL REPLACEMENT
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:
Oil 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: 
Oil tank plug 1 
Oil filler cap 2
Drain bolt (with gasket) 3 
Oil filter drain bolt (O-ring) 4 
Drain bolt (with gasket) 5 
Drain bolt (with gasket) 6
Drain the crankcase and oil tank
(frame) of its oil.
4. Remove:
Engine skid plate
Engine oil hose clamp 1 
Bolt (engine oil hose) 2 
Engine oil hose 3 
Oil strainer (frame) 4 
5. Clean:
Oil 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:
Plain washer 1 
Oil strainer (frame) 2 
Engine oil hose 3 
Bolt (engine oil hose) 4 
Engine oil hose clamp 5 
Engine skid plate
8. Install:
Gaskets
Oil filter drain bolt
Drain bolt (crankcase rear)
Drain bolt (crankcase left)
Drain bolt (frame)
9. Fill:
Crankcase
10. Install:
Oil filler plug
11. Inspect:
Engine (for oil leaks)
Oil level
Refer to “ENGINE OIL LEVEL INSPEC-
TION”. Replacement steps:
Remove the exhaust pipe.
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:
Total amount:
1.2 L (1.06 Imp qt, 1.27 US qt)
Periodic oil change:
1.0 L (0.88 Imp qt, 1.06 US qt)
With oil filter replacement:
1.1 L (0.97 Imp qt, 1.16 US qt)
New
T R..90 Nm (9.0 m · kg, 65 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)
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..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..23 Nm (2.3 m · kg, 17 ft · lb) 
						

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PILOT SCREW ADJUSTMENT
12. 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)
PILOT SCREW ADJUSTMENT
1. Adjust:
Pilot screw 1 
* Except for USAAdjusting steps:
NOTE:
To optimize the fuel flow at a smaller throttle
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 num-
ber as the factory-set number of turns out.
Turn in the pilot screw until it is lightly
seated.
Turn out the pilot screw by the factory-set
number of turns.
Pilot screw:
1-3/4 turns out (example)
*1-1/2 turns out (example) 
						

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INSP
ADJIDLE SPEED ADJUSTMENT/
VALVE CLEARANCE ADJUSTMENT
EC35M021
IDLE SPEED ADJUSTMENT
1. Start the engine and thoroughly warm it
up.
2. Adjust:
Idle speed
Adjustment steps:
Adjust the pilot screw.
Refer to “PILOT SCREW ADJUSTMENT”
section.
Turn the throttle stop screw 1 until the
engine runs at the lowest possible speed.
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:
1,700 ~ 1,900 r/min
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:
Carburetor
Refer to “CARBURETOR” section in
the CHAPTER 4.
Spark plug cap 
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 
						

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INSP
ADJ
VALVE CLEARANCE ADJUSTMENT
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.
NOTE:
In order to be sure that the piston is at Top
Dead Center, the punch mark c on the
exhaust camshaft and the punch mark d on
the intake camshaft must align with the cyl-
inder head surface, as shown in the illustra-
tion.
Measure the valve clearance e using a
feeler gauge 1.
NOTE:
Record the measured reading if the clear-
ance is incorrect.
b
a 
						

							 
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INSP
ADJ
 
VALVE CLEARANCE ADJUSTMENT 
5. Adjust: 
 
Valve clearance  
Adjustment steps: 
 
Loosen the timing chain tensioner cap
bolt. 
 
Remove the timing chain tensioner and
camshaft caps.
NOTE:
 
Remove the camshaft cap bolts in a criss-
cross pattern from the outside working 
inwards. 
 
Remove the camshaft (exhaust   
1  
 and
intake   
2  
).
NOTE:
 
Attach a wire   
3  
 to the timing chain to pre- 
vent it from falling into the crankcase. 
 
Remove the valve lifters   
4  
 and the pads   
5  
.
NOTE:
 
 
Place a rag in the timing chain space to
prevent pads from falling into the crank-
case. 
 
Identity each valve lifter and pad position
very carefully so that they can be rein- 
stalled in their original place. 
 
Select the proper pad using the pad
selecting table.  
Pad rangePad Availability:
25 increments
No. 120
~
No. 2401.20 mm
~
2.40 mmPads are available in 
0.05 mm increments
NOTE:
 
The thickness   
a  
 of each pad is indicated in
hundreths of millimeters on the pad upper 
surface.
1
2
3 
						

							 
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ADJ
 
 
Round off the last digit of the installed pad
number to the nearest increment.  
Last digit of pad 
numberRounded value
0, 1 or 2 0
4, 5 or 6 5
8 or 9 10
EXAMPLE:  
Installed pad number = 148
Rounded off value = 150
NOTE:
 
Pads can only be selected in 0.05 mm incre- 
ments. 
 
Locate 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.
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) 
VALVE CLEARANCE ADJUSTMENT 
						

							 
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INSP
ADJ
 
6. Install: 
 
All removed parts
NOTE:
 
Install all removed parts in reversed order of 
their removal. Note the following points. 
 
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 
						

							 
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VALVE CLEARANCE ADJUSTMENT 
INTAKE 
MEASURED 
CLEARANCEINSTALLED PAD NUMBER
120 125 130 135 140 145 150 155 160 165 170
175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.00 ~ 0.04 120 125 130 135 140 145 150 155
160165 170 175 180 185 190 195 200 205 210 215 220 225 230
0.05 ~ 0.09
120 125 130 135 140 145 150 155 160 165170 175 180 185 190 195 200 205 210 215 220 225 230 235
0.10 ~ 0.15
STANDARD CLEARANCE
0.16 ~ 0.20125130135140145150155160165170175180 185 190 195 200 205 210 215 220 225 230 235240
0.21 ~ 0.25130135140145150155160165170175180185 190 195 200 205 210 215 220 225 230 235240
0.26 ~ 0.30 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.31 ~ 0.35 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.36 ~ 0.40 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.41 ~ 0.45 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.46 ~ 0.50 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.51 ~ 0.55 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.56 ~ 0.60 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.61 ~ 0.65 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.66 ~ 0.70 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.71 ~ 0.75 180 185 190 195 200 205 210 215 220 225 230 235240
0.76 ~ 0.80 185 190 195 200 205 210 215 220 225 230 235240
 
VALVE CLEARANCE (cold):
0.10 ~ 0.15 mm
Example: Installed is 175
Measured clearance is 0.22 mm
Replace 175 pad with 185 pad
Pad number: (example)
Pad No. 175 = 1.75 mm
Pad No. 185 = 1.85 mm 
0.81 ~ 0.85 190 195 200 205 210 215 220 225 230 235
240
0.86 ~ 0.90 195 200 205 210 215 220 225 230 235240
0.91 ~ 0.95 200 205 210 215 220 225 230 235240
0.96 ~ 1.00 205 210 215 220 225 230 235240
1.01 ~ 1.05 210 215 220 225 230 235240
1.06 ~ 1.10 215 220 225 230 235240
1.11 ~ 1.15 220 225 230 235240
1.16 ~ 1.20 225 230 235240
1.21 ~ 1.25 230 235240
1.26 ~ 1.30 235240
1.31 ~ 1.35 240
 
EXHAUST 
MEASURED 
CLEARANCEINSTALLED PAD NUMBER
120 125 130 135 140 145 150 155 160 165 170
175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.00 ~ 0.04 120 125 130 135 140 145
150155 160 165 170 175 180 185 190 195 200 205 210 215 220
0.05 ~ 0.09
120 125 130 135 140 145 150 155160 165 170 175 180 185 190 195 200 205 210 215 220 225
0.10 ~ 0.14
120 125 130 135 140 145 150 155 160165 170 175 180 185 190 195 200 205 210 215 220 225 230
0.15 ~ 0.19120125130135140145150155160165170 175 180 185 190 195 200 205 210 215 220 225230235
0.20 ~ 0.25
STANDARD CLEARANCE
0.26 ~ 0.30 125 130 135 140 145 150 155 160 165 170 175180 185 190 195 200 205 210 215 220 225230235240
0.31 ~ 0.35130135140145150155160165170175180185 190 195 200 205 210 215 220 225230235240
0.36 ~ 0.40 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.41 ~ 0.45 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.46 ~ 0.50 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.51 ~ 0.55 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.56 ~ 0.60 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.61 ~ 0.65 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.66 ~ 0.70 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.71 ~ 0.75 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.76 ~ 0.80 175 180 185 190 195 200 205 210 215 220 225230235240
0.81 ~ 0.85 180 185 190 195 200 205 210 215 220 225230235240
0.86 ~ 0.90 185 190 195 200 205 210 215 220 225230235240
 
VALVE CLEARANCE (cold):
0.20 ~ 0.25 mm
Example: Installed is 175
Measured clearance is 0.32 mm
Replace 175 pad with 185 pad
Pad number: (example)
Pad No. 175 = 1.75 mm
Pad No. 185 = 1.85 mm 
0.91 ~ 0.95 190 195 200 205 210 215 220 225
230235240
0.96 ~ 1.00 195 200 205 210 215 220 225230235240
1.01 ~ 1.05 200 205 210 215 220 225230235240
1.06 ~ 1.10 205 210 215 220 225230235240
1.11 ~ 1.15 210 215 220 225230235240
1.16 ~ 1.20 215 220 225230235240
1.21 ~ 1.25 220 225230235240
1.26 ~ 1.30 225230235240
1.31 ~ 1.35 230235240
1.36 ~ 1.40 235240
1.41 ~ 1.45 240 
						

							 
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SPARK ARRESTER CLEANING (For USA)
WARNING
 
 
Be sure the exhaust pipe and muffler are
cool before cleaning the spark arrester. 
 
Do not start the engine when cleaning the 
exhaust system. 
1. Remove: 
 
Bolt (spark arrester)  
1  
 
1
1
 
2. Remove: 
 
Spark arrester  
1 
 
Pull the spark arrester out of the muf-
fler.
1
 
3. Clean: 
 
Spark arrester
Tap the spark arrester lightly, then use
a wire brush to remove any carbon
deposits.
4. Install: 
 
Spark arrester
Insert the spark arrester into the muffler
and align the bolt holes. 
 
Bolt (spark arrester)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
 
SPARK ARRESTER CLEANING (For USA)