2010 YAMAHA YZ450F oil pressure

4-27
CLUTCH
CLUTCH
REMOVING THE CLUTCH
Order Part name Q'ty Remarks
Drain the engine oil. Refer to "CHANGING THE ENGINE OIL"
section in the CHAPTER 3.
Brake pedal Refer to "ENGINE REMOVAL" section.
Clutch cable Disconnect at engine side.
1 Clutch cover 1
2 Gasket 1
3 Clutch spring 6
4 Pressure plate 1
5 Push rod 1 1
6 Circlip 1
7 Washer 1
8 Bearing 1
9Ball 1
10 Push rod 2 1
11 Clutch plate 7
12 Friction plate 8
13 Nut (clutch boss) 1 Refer to removal section.

4-30
CLUTCH
INSTALLING THE CLUTCH
1. Install:
• Primary driven gear "1"
• Thrust washer "2"
• Clutch boss "3"
Apply the engine oil on the primary
driven gear inner circumference.
2. Install:
• Conical washer "1"
• Nut (clutch boss) "2"
Make sure to tighten to specifica-
tion; otherwise, it may damage the
other part that is fastened togeth-
er.
• Apply engine oil to the threads and
contact surface of the clutch boss
nut.
• Apply engine oil to the contact sur-
faces of the conical washer.
• Install the conical washer with its
convex surface "a" outward.
• Use the clutch holding tool "3" to
hold the clutch boss.
A. For USA and CDN
B. Except for USA and CDN3. Install:
• Friction plate "1"
• Clutch plate "2"
• Install the clutch plates and friction
plates alternately on the clutch
boss, starting with a friction plate
and ending with a friction plate.
• Apply the engine oil on the friction
plates and clutch plates.
4. Install:
•Bearing "1"
• Washer "2"
• Circlip "3"
To push rod 1 "4".
Apply the engine oil on the bearing
and washer.
5. Install:
• Push rod 2 "1"
• Ball "2"
• Push rod 1 "3"
Apply the engine oil on the push rod
1, 2 and ball.
6. Install:
• Pressure plate "1"7. Install:
• Clutch spring
• Bolt (clutch spring)
Tighten the bolts in stage, using a
crisscross pattern.
8. Install:
• O-ring (clutch cover) "1"
9. Install:
• Clutch cover "1"
• Bolt (clutch cover)
Tighten the bolts in stage, using a
crisscross pattern.
Nut (clutch boss):
75 Nm (7.5 m•kg, 54
ft•lb)
Clutch holding tool:
YM-91042/90890-04086
Bolt (clutch spring):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (clutch cover):
10 Nm (1.0 m•kg, 7.2
ft•lb)

4-47
ENGINE REMOVAL
ENGINE REMOVAL
REMOVING THE ELECTRONIC PARTS
Order Part name Q'ty Remarks
Hold the machine by placing the suitable stand
under the frame.Refer to "HANDLING NOTE".
SeatRefer to "SEAT AND SIDE COVERS" sec-
tion.
Fuel tankRefer to "FUEL TANK" section in the
CHAPER 6.
Air filter caseRefer to "THROTTLE BODY" section in the
CHAPRE 6.
Radiator Refer to "RADIATOR" section.
1 Rectifier/regulator 1
2 Ignition coil bracket 1
3 Ignition coil 1
4 Atmospheric pressure sensor 1
5 Condenser 1
6 AC magneto lead 1 Disconnect.
7 Coolant temperature sensor coupler 1 Disconnect.

5-20
FRONT FORK
5. Measure:
• Oil level (left and right) "a"
Out of specification → Adjust.
6. Tighten:
• Locknut "1"
Fully finger tighten the locknut onto
the damper assembly.
7. Loosen:
• Compression damping adjuster
"1"
• Loosen the compression damping
adjuster finger tight.
• Record the set position of the ad-
juster (the amount of turning out the
fully turned in position).
8. Install:
• Base valve "1"
To damper assembly "2".
First bring the damper rod pressure to
a maximum. Then install the base
valve while releasing the damper rod
pressure.
9. Check:
• Damper assembly
Not fully stretched → Repeat the
steps 2 to 8.
10. Tighten:
• Base valve "1"
Hold the damper assembly with the
cap bolt ring wrench "2" and use the
cap bolt wrench "3" to tighten the
base valve with specified torque.
11. After filling, pump the damper as-
sembly "1" slowly up and down
more than 10 times to distribute
the fork oil.12. While protecting the damper as-
sembly "1" with a rag and com-
pressing fully, allow excessive oil
to overflow on the base valve
side.
Take care not to damage the damp-
er assembly.
13. Allow the overflowing oil to es-
cape at the hole "a" in the damper
assembly.
14. Check:
• Damper assembly smooth move-
ment
Tightness/binding/rough spots →
Repeat the steps 2 to 13.
15. Install:
• Dust seal "1"
• Stopper ring "2"
• Oil seal "3"
• Oil seal washer "4"
• Slide metal "5"
To inner tube "6".
• Apply the fork oil on the inner tube.
• When installing the oil seal, use vi-
nyl seat "a" with fork oil applied to
protect the oil seal lip.
• Install the oil seal with its manufac-
ture's marks or number facing the
axle holder side.
Standard oil level:
145-148 mm (5.71-5.83
in)
From top of fully
stretched damper as-
sembly.
Base valve:
29 Nm (2.9 m•kg, 21 ft•
lb)
Cap bolt wrench:
YM-01500/90890-01500
Cap bolt ring wrench:
YM-01501/90890-01501

5-38
REAR SHOCK ABSORBER
HANDLING NOTE
• Support the machine securely so
there is no danger of it falling
over.
• This rear shock absorber is pro-
vided with a separate type tank
filled with high-pressure nitro-
gen gas. To prevent the danger
of explosion, read and under-
stand the following information
before handling the shock ab-
sorber. The manufacturer can
not be held responsible for prop-
erty damage or personal injury
that may result from improper
handling.
• Never tamper or attempt to dis-
assemble the cylinder or the
tank.
• Never throw the rear shock ab-
sorber into an open flame or
other high heat. The rear shock
absorber may explode as a re-
sult of nitrogen gas expansion
and/ or damage to the hose.
• Be careful not to damage any
part of the gas tank. A damaged
gas tank will impair the damp-
ing performance or cause a
malfunction.
• Take care not to scratch the
contact surface of the piston
rod with the cylinder; or oil
could leak out.
• Never attempt to remove the
plug at the bottom of the nitro-
gen gas tank. It is very danger-
ous to remove the plug.
• When scrapping the rear shock
absorber, follow the instruc-
tions on disposal.
NOTES ON DISPOSAL (YAMAHA
DEALERS ONLY)
Before disposing the rear shock ab-
sorber, be sure to extract the nitrogen
gas from valve "1". Wear eye protec-
tion to prevent eye damage from es-
caping gas and/or metal chips.
To dispose of a damaged or worn-
out rear shock absorber, take the
unit to your Yamaha dealer for this
disposal procedure.
REMOVING THE BEARING
1. Remove:
• Stopper ring (upper bearing) "1"
Press in the bearing while pressing its
outer race and remove the stopper
ring.
2. Remove:
• Upper bearing "1"
Remove the bearing by pressing its
outer race.
3. Remove:
• Lower bearing "1"
Remove the bearing by pressing its
outer race.
CHECKING THE REAR SHOCK
ABSORBER
1. Inspect:
• Damper rod "1"
Bends/damage→Replace rear
shock absorber assembly.
• Shock absorber "2"
Oil leaks→Replace rear shock
absorber assembly.
Gas leaks→Replace rear shock
absorber assembly.
• Spring "3"
Damage→Replace spring.
Fatigue→Replace spring.
Move spring up and down.
• Spring guide "4"
Wear/damage→Replace spring
guide.
• Bearing "5"
Free play exists/unsmooth revolu-
tion/rust →Replace.
INSTALLING THE BEARING
1. Install:
• Upper bearing "1"
Install the bearing parallel until the
stopper ring groove appears by
pressing its outer race.
Do not apply the grease on the
bearing outer race because it will
wear the rear shock absorber sur-
face on which the bearing is press
fitted.

7-1
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
ELECTRICAL
This section is intended for those who have basic knowledge and skill concerning the servicing of Yamaha motorcycles
(e.g., Yamaha dealers, service engineers, etc.) Those who have little knowledge and skill concerning servicing are request-
ed not to undertake inspection, adjustment, disassembly, or reassembly only by reference to this manual. It may lead to
servicing trouble and mechanical damage.
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
ELECTRICAL COMPONENTS
1. Crankshaft position sensor
2. AC magneto
3. Rectifier/regulator
4. Condenser
5. Fuel pump
6. Engine stop switch
7. ECU
8. Ignition coil9. Spark plug
10. Fuel injector
11. Intake air temperature sensor
12. Intake air pressure sensor
13. Throttle position sensor
14. Atmospheric pressure sensor
15. Coolant temperature sensor
16. Coupler for connecting optional part
7

7-2
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
WIRING DIAGRAM
1. Crankshaft position sensor
2. AC magneto
3. Rectifier/regulator
4. Condenser
5. Fuel pump
6. Engine stop switch
7. ECU
8. Ignition coil
9. Spark plug
10. Fuel injector
11. Intake air temperature sensor
12. Intake air pressure sensor
13. Throttle position sensor
14. Atmospheric pressure sensor
15. Coolant temperature sensor
16. Coupler for connecting optional part COLOR CODE
BBlack
Br Brown
Gy Gray
LBlue
Lg Light green
O Orange
PPink
RRed
WWhite
YYellow
B/L Black/Blue
B/R Black/Red
B/W Black/White
B/Y Black/Yellow
Br/W Brown/White
P/W Pink/White
R/B Red/Black
R/W Red/White
STOPON
Gy
Gy
B
B
/L
W1
W2
W2 O
R /B
R RR
R
R
R R
Lg
Lg Lg L
P
/W
P YB
/RB
B B
B
B BB
BB/W
B /W
B/W Br
/WGy
B /L
W1 W1
W2 W2 B
/Y
B /Y Br
B /R
R /W
OO
R /B
RR
R
L
P/W
P YL
L
LY
Br /WB /L
B /L
B/L
B
B/L
B/L
Br
W1
Br
/W
W2
R
R O
B/L
L
Y
B /L
Br
R
P
Gy
Gy
B /R
B
/R
R/WB /Y
B
/L
W1
W2
W1 R
R R
B
B
/Y
Lg Lg
O
R /B
R/B
Br /W
P /W P
/W
L L
Y
B /L B
/L
B/L
Br
B
B /W
B
/W
B
B
B L
B
/L
P

7-11
FUEL INJECTION SYSTEM
SENSOR OPERATION TABLE
Diagnos-
tic code
No.ItemActuation or
displayChecking methodActuation or LCD standard display
values
D01 Throttle angle DisplayDisplays the throttle angle. 0–125°
Check with throttle fully closed. When throttle is fully closed:15–19°
Check with throttle fully open. When throttle is fully
opened:95–101 °
D02 Atmosphere DisplayDisplays the atmospheric pres-
sure.
• Measure the atmospheric pres-
sure.0–126 kPa
Displays the atmospheric pressure
according to the elevation and
weather.
Example
0 m above sea level: Approx: 101
kPa
3000 m above sea level:Approx: 70
kPa
D03 Intake air pressure DisplayDisplays the intake air pressure.
• Check the intake manifold pres-
sure.
• Check that the intake air pres-
sure changes while the engine is
being cranked.0–126 kPa
While the engine is stopped: Dis-
plays the atmospheric pressure ac-
cording to the elevation and
weather.
Example
0 m above sea level: Approx: 101
kPa
3000 m above sea level:Approx: 70
kPa
While the engine is being cranked:
Displays the intake air pressure.
D05 Intake air temperature DisplayDisplays the intake air tempera-
ture.
• Check the temperature in the in-
take manifold.-20–100°C
Cold engine: Displayed tempera-
ture is close to the ambient temper-
ature.
Warm engine: Displayed tempera-
ture is approximately 20 °C higher
than the ambient temperature.
D06 Coolant temperature DisplayDisplays the coolant temperature.
• Check the coolant temperature.-20–150°C
Cold engine: Displayed tempera-
ture is close to the ambient temper-
ature.
Warm engine: Displayed tempera-
ture is the current coolant tempera-
ture.
D08 Lean angle sensor DisplayDisplays the lean angle sensor
output voltage.
Remove the ECU and incline it 45°
or more.0–5.0 V
1.0 V: Upright
4.0 V: Overturned
D30 Ignition coil ActuationCheck that power is supplied to
the ignition coil.
• Check that a spark is generated.
• Illuminates the engine trouble
warning light.Actuates the ignition coil for five
times every second.
The "WARNING" LED on the FI di-
agnostic tool comes on each time
the fuel injector is actuated.