YAMAHA YZ450F 2014 Owners Manual

OIL PUMP AND BALANCER GEAR
5-56
EAS1SL1266REMOVING THE BALANCER
1. Straighten the lock washer tab.
2. Loosen:
• Balancer nut “1”
• Primary drive gear nut “2”
• Balancer weight gear nut “3”
TIP
Place an aluminum plate “a” between the teeth
of the balancer drive gear “4” and balancer
weight gear “5”.
EAS1SL1267CHECKING THE PRIMARY DRIVE GEAR,
BALANCER SHAFT DRIVE GEAR, AND
BALANCER WEIGHT GEAR
1. Check:
• Primary drive gear “1”
• Balancer shaft drive gear “2”
• Balancer weight gear “3”
Wear/damage  Replace.
EAS1SL1268CHECKING THE BALANCER
1. Check:
•Balancer
Crack/damage  Replace.
EAS1SL1269CHECKING THE OIL PUMP
1. Check:
• Oil pump drive gear
• Oil pump driven gear
• Oil pump housing
• Oil pump housing cover
Cracks/damage/wear  Replace the defec-
tive part(s).
2. Measure:
• Inner-rotor-to-outer-rotor-tip clearance “a”
• Outer-rotor-to-oil-pump-housing clearance
“b”
• Oil-pump-housing-to-inner-rotor-and-outer-
rotor clearance “c”
Out of specification  Replace the oil pump.
1
5
4
2
a
43
a
5
Inner-rotor-to-outer-rotor-tip
clearance
Less than
0.150 mm (0.0059 in)
Outer-rotor-to-oil-pump-housing
clearance
0.13–0.18 mm (0.0051–0.0071 in)
Oil-pump-housing-to-inner-and-
outer-rotor

clearance
0.06–0.11 mm (0.0024–0.0043 in)

OIL PUMP AND BALANCER GEAR
5-57
3. Check:
• Oil pump operation
Rough movement  Repeat steps (1) and
(2) or replace the defective part(s).
EAS1SL1270ASSEMBLING THE OIL PUMP
1. Install:
• Oil pump drive shaft “1”
• Inner rotor “2”
• Dowel pin “3”
TIP
• Apply the engine oil on the oil pump drive
shaft and inner rotor.
• Fit the dowel pin into the groove in the inner
rotor.
2. Install:
• Outer rotor “1”
TIP
Apply the engine oil on the outer rotor.
3. Install:
• Oil pump cover “1”
• Oil pump cover screw “2”
EAS1SL1271INSTALLING THE OIL PUMP AND BALANC-
ER GEAR
1. Install:
• Oil pump assembly “1”
• Oil pump assembly bolt “2”
ECA1DX1023
1. Inner rotor
2. Outer rotor
3. Oil pump housing
b
a 1
2
3
c
21
3
Oil pump cover screw
2 Nm (0.2 m·kgf, 1.4 ft·lbf)
Oil pump assembly bolt
5 Nm (0.5 m·kgf, 3.6 ft·lbf)
LOCTITE®
1
E
T R..
2
1
T R..
1
2
LT

OIL PUMP AND BALANCER GEAR
5-58
NOTICE
After tightening the bolts, make sure that
the oil pump turns smoothly.
2. Install:
• Balancer weight gear “1”
TIP
Install the balancer weight gear and balancer
shaft with their lower splines “a” aligning with
each other.
3. Install:
• Balancer drive gear “1”
TIP
• Align the punched mark “a” on the balancer
drive gear with the punched mark “b” on the
balancer weight gear.
• Install the balancer drive gear and crankshaft
with the lower splines “c” aligning with each
other.
4. Install:
• Lock washer “1”
• Balancer weight gear nut “2”
• Primary drive gear “3”
• Conical washer “4”
• Primary drive gear nut “5”
• Straight key “6”
•Balancer “7”
• Lock washer “8”
• Balancer nut “9”
TIP
• Apply engine oil to the contact surface and
threaded portion of the primary drive gear nut.
• Apply engine oil to the contact surfaces of the
conical washer.
• Place an aluminum plate “a” between the
teeth of the balancer drive gear “10” and bal
-
ancer weight gear “11”.
• Install the conical washer with its convex sur-
face “b” outward.
5. Bend the lock washer tab.
Balancer weight gear nut
50 Nm (5.0 m·kgf, 36 ft·lbf)
Primary drive gear nut
100 Nm (10 m·kgf, 72 ft·lbf)
New
T R..
New
T R..
Balancer nut
45 Nm (4.5 m·kgf, 33 ft·lbf)
New
T R..
1
2 11
10
a
3 45
1011
a
b
3

AC MAGNETO
5-59
EAS1SL1272
AC MAGNETO
Removing the AC magneto
OrderPart nameQ’tyRemarks
Engine oilDrain.Refer to “CHANGING THE ENGINE OIL” on page 3-15.
SeatRefer to “GENERAL CHASSIS” on page 4-1.
Air scoop (left)Refer to “GENERAL CHASSIS” on page 4-1.
1AC magneto leadDisconnect.
2Crankshaft position sensor lead1Disconnect.
3Shift pedal1
4Left crankcase cover1
5Gaskets1
6Dowel pin2
7Holder1
8Stator assembly1
9Rotor1
10Woodruff key1
For installation, reverse the removal proce-dure.
110
2
4 7 5 8 3
96
10 Nm (1.0 mkgf, 7.2 ftIbf)T.R.
8 Nm (0.8 mkgf, 5.8 ftIbf)T.R.
8 Nm (0.8 mkgf, 5.8 ftIbf)T.R.
10 Nm (1.0 mkgf, 7.2 ftIbf)T.R.
10 Nm (1.0 mkgf, 7.2 ftIbf)T.R.
65 Nm (6.5 mkgf, 47 ftIbf)T.R.
New
LT
6
LT
LT

AC MAGNETO
5-60
EAS1SL1273REMOVING THE AC MAGNETO
1. Remove:
• Nut (rotor) “1”
• Washers
2. Remove:
• Rotor “1”
Use the rotor puller “2” to remove the rotor.
• Woodruff key
EAS1SL1274CHECKING THE AC MAGNETO
1. Check:
• Rotor inner surface “a”
• Stator outer surface “b”
Damage  Inspect the crankshaft runout
and crankshaft bearing.
EAS1SL1275
CHECKING THE WOODRUFF KEY
1. Check:
• Woodruff key “1”
Damage  Replace.
EAS1SL1276INSTALLING THE AC MAGNETO
1. Install:
• Stator “1”
• Screw (stator) “2”
• Crankshaft position sensor “3”
• Bolt (crankshaft position sensor) “4”
• Holder “5”
• Bolt (holder) “6”
TIP
• Apply the sealant to the grommet of the AC
magneto lead.
• Tighten the stator screws using the T25 bit.
• Pass the AC magneto lead “a” through the
crankcase cover side.
Rotor puller
90890-04151
YM-04151
1
ab
Screw (stator)
8 Nm (0.8 m·kgf, 5.8ft·lbf)
LOCTITE®
Bolt (crankshaft position sensor)
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
LOCTITE®
Holder
8 Nm (0.8 m·kgf, 5.8 ft·lbf)
LOCTITE®
Three Bond No.1215®
90890-85505
T R..
T R..
26
5
4
3
4a
1
LT
LT

AC MAGNETO
5-61
2. Install:
• Woodruff key “1”
• Rotor “2”
TIP
• Clean the contact surfaces of the tapered por-
tions of the crankshaft and rotor.
• When installing the woodruff key, make sure
that its flat surface “a” is in parallel with the
crankshaft center line “b”.
• When installing the rotor, align the keyway “c”
of the rotor with the woodruff key.
3. Install:
• Washers
• Nut (rotor) “1”
4. Install:
• Dowel pin “1”
• Gasket (left crankcase cover) “2”
• Left crankcase cover “3”
• Lead holder “4”
• Bolt (left crankcase cover) “5”
TIP
Tighten the bolts in stages and in a crisscross
pattern.
5. Connect:
• AC magneto lead
Refer to “CABLE ROUTING DIAGRAM” on
page 2-33.
Nut (rotor)
65 Nm (6.5 m·kgf, 47 ft·lbf)
Bolt (left crankcase cover)
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
b11
c
2 a
T R..
1
New
T R..
1
1
2
3
5
5
5
5
4
45

CRANKCASE
5-62
EAS1SL1277
CRANKCASE
Separating the crankcase
OrderPart nameQ’tyRemarks
EngineRefer to “ENGINE REMOVAL” on page 5-1.
PistonRefer to “CYLINDER AND PISTON” on page 5-32.
BalancerRefer to “OIL PUMP AND BALANCER GEAR” on page 5-54.
Kick shaft assemblyRefer to “KICKSTATER” on page 5-46.
SegmentRefer to “SHIFT SHAFT” on page 5-49.
StatorRefer to “AC MAGNETO” on page 5-59.
1Timing chain guide (exhaust side)1
2Timing chain guide stopper plate1
3Timing chain1
4Bolt [L = 45 mm (1.77 in)]6
5Bolt [L = 65 mm (2.56 in)]4
6Bolt [L = 75 mm (2.95 in)]2
7Right crankcase1
8Left crankcase1
9Dowel pin2
10 Nm (1.0 m•kgf, 7.2 ft•Ibf)T.R.
12 Nm (1.2 m•kgf, 8.7 ft•Ibf)T.R.
12 Nm (1.2 m•kgf, 8.7 ft•Ibf)T.R.
12 Nm (1.2 m•kgf, 8.7 ft•Ibf)T.R.
3
1 5
2
6410 55
4
4
446
97
8
9
LT

CRANKCASE
5-63
10Crankshaft1
For assembly, reverse the disassemble pro-cedure.
Separating the crankcase
Order Part name Q’ty Remarks
10 Nm (1.0 m•kgf, 7.2 ft•Ibf)T.R.
12 Nm (1.2 m•kgf, 8.7 ft•Ibf)T.R.
12 Nm (1.2 m•kgf, 8.7 ft•Ibf)T.R.
12 Nm (1.2 m•kgf, 8.7 ft•Ibf)T.R.
3
1 5
2
6410 55
4
4
446
97
8
9
LT

CRANKCASE
5-64
Removing the bearing and oil seal
OrderPart nameQ’tyRemarks
TransmissionRefer to “TRANSMISSION” on page 5-70.
Shift cam and shift forkRefer to “TRANSMISSION” on page 5-70.
1Circlip1
2Oil seals3
3Bearing11
For installation, reverse the removal proce-dure.
LT
LT
LT
LT
LT
1
22
3
3
33
3
3
3 3
33
New
NewLT

CRANKCASE
5-65
EAS1SL1278DISASSEMBLING THE CRANKCASE
1. Separate:
• Right crankcase
• Left crankcase
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Remove the crankcase bolts.
TIP
Loosen each bolt 1/4 of a turn at a time and af-
ter all the bolts are loosened, remove them.
b. Remove the right crankcase “1.”
TIP
• Place the crankcase with its left side down-
ward and split it by inserting a screwdriver tip
into the splitting slit “a” in the crankcase.
• Lift the right crankcase horizontally while light-
ly patting the crankcase splitting slit and the
engine mounting boss using a soft hammer,
and leave the crankshaft and the transmission
with the left crankcase.
ECA33DD041
NOTICE
Use soft hammer to tap on the case half.
Tap only on reinforced portions of case. Do
not tap on gasket mating surface. Work
slowly and carefully. Make sure the case
halves separate evenly. If the cases do not
separate, check for a remaining case bolt or
fitting. Do not force.
c. Remove the dowel pins and O-ring.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS1SL1279REMOVING THE CRANKCASE BEARING
1. Remove:
• Bearing “1”
TIP
• Remove the bearing from the crankcase by
pressing its inner race.
• Do not use the removed bearing.
EAS1SL1280CHECKING THE TIMING CHAIN, TIMING
CHAIN GUIDE, OIL STRAINER
1. Check:
• Timing chain
Stiffness  Replace the camshaft sprocket,
timing chain and crankshaft sprocket as a
set.
2. Check:
• Timing chain guide
Damage/wear  Replace
EAS1SL1281CHECKING THE CRANKCASE
1. Wash:
• Crankcase
TIP
• Wash the crankcase in a mild solvent.
• Remove any remaining gasket from the
crankcase mating surface.
1
a