YAMAHA YZ450F 2016 Owners Manual

OIL PUMP AND BALANCER GEAR
5-56
Removing the balancer
Order Part name Q’ty Remarks
Primary driven gear Refer to “CLUTCH” on page 5-38.
Right crankcase cover Refer to “CLUTCH” on page 5-38.
Stator Refer to “AC MAGNETO” on page 5-61.
1 Nut (balancer) 1
2 Nut (primary drive gear) 1
3 Nut (balancer shaft driven gear) 1
4 Lock washer 1
5Balancer 1
6 Straight key 1
7 Conical washer 1
8 Primary drive gear 1
9 Balancer shaft drive gear 1
10 Lock washer 1
11 Balancer weight gear 1
For installation, reverse the removal proce-
dure.
45 Nm (4.5 mkgf, 33 ftIbf)T.R
.
100 Nm (10 mkgf, 72 ftlbf)T.R.
50 Nm (5.0 mkgf, 36 ftIbf)T.R
.
New

OIL PUMP AND BALANCER GEAR
5-57
EASB111265REMOVING 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”.
EASB111266CHECKING 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.
EASB111267CHECKING THE BALANCER
1. Check:
•Balancer
Crack/damage  Replace.
EASB111268CHECKING 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

OIL PUMP AND BALANCER GEAR
5-58
3. Check:
• Oil pump operation
Rough movement  Repeat steps (1) and
(2) or replace the defective part(s).
EASB111269
ASSEMBLING 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” Inner-rotor-to-outer-rotor-tip
clearance
Less than 0.150 mm (0.0059 in)
Limit
0.20 mm (0.0079 in)
Outer-rotor-to-oil-pump-housing
clearance
0.13–0.18 mm (0.0051–0.0071 in)
Limit
0.24 mm (0.0094 in)
Oil-pump-housing-to-inner-and-
outer-rotor
clearance
0.06–0.11 mm (0.0024–0.0043 in)
Limit
0.17 mm (0.0067 in)
1. Inner rotor
2. Outer rotor
3. Oil pump housing
b
a 1
2
3
c
Oil pump cover screw
2.0 Nm (0.20 m·kgf, 1.4 ft·lbf)
21
3
1
E
T R..
2
1

OIL PUMP AND BALANCER GEAR
5-59
EASB111270INSTALLING THE OIL PUMP AND BALANC-
ER GEAR
1. Install:
• Oil pump assembly “1”
• Oil pump assembly bolt “2”
ECA1DX1023
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. Oil pump assembly bolt
5 Nm (0.5 m·kgf, 3.6 ft·lbf)
LOCTITE®
T R..
1
2
LT
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)
Balancer nut
45 Nm (4.5 m·kgf, 33 ft·lbf)
New
T R..
New
T R..
New
T R..
1
2 11
10
a

OIL PUMP AND BALANCER GEAR
5-60
5. Bend the lock washer tab.
3 45
1011
a
b
3

AC MAGNETO
5-61
EASB111271
AC MAGNETO
Removing the AC magneto
Order Part name Q’ty Remarks
Engine oilDrain.
Refer to “CHANGING THE ENGINE OIL” on
page 3-15.
Seat Refer to “GENERAL CHASSIS” on page 4-1.
Air scoop (left) Refer to “GENERAL CHASSIS” on page 4-1.
1 AC magneto coupler 1 Disconnect.
2 Crankshaft position sensor coupler 1 Disconnect.
3 Shift pedal 1
4 Left crankcase cover 1
5 Gaskets 1
6 Dowel pin 2
7Holder 1
8 Stator assembly 1
9 Rotor 1
10 Woodruff key 1
For installation, reverse the removal proce-
dure.
110
2
4 7 5 8 3
96
12 Nm (1.2 m kgf, 8.7 ft Ibf)T.R.
8 Nm (0.8 m kgf, 5.8 ft Ibf)T.R.
8 Nm (0.8 m kgf, 5.8 ft Ibf)T.R.
65 Nm (6.5 m kgf, 47 ft Ibf)T.R.
New
LT
6
LT
LT
10 Nm (1.0 m kgf, 7.2 ft Ibf)T.R.
10 Nm (1.0 m kgf, 7.2 ft Ibf)T.R.

AC MAGNETO
5-62
EASB111272REMOVING THE AC MAGNETO
1. Remove:
• Nut (rotor) “1”
• Washers
2. Remove:
• Rotor “1”
Use the rotor puller “2” to remove the rotor.
• Woodruff key
EASB111273CHECKING THE AC MAGNETO
1. Check:
• Rotor inner surface “a”
• Stator outer surface “b”
Damage  Inspect the crankshaft runout
and crankshaft bearing.
EASB111274
CHECKING THE WOODRUFF KEY
1. Check:
• Woodruff key “1”
Damage  Replace.
EASB111275INSTALLING 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..

AC MAGNETO
5-63
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 2-31.
Nut (rotor)
65 Nm (6.5 m·kgf, 47 ft·lbf)
26
5
4
3
4a
1
LT
LT
b11
c
2 a
T R..
1
Bolt (left crankcase cover)
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
New
T R..
1
1
2
3
5
5
5
5
4
45

CRANKCASE
5-64
EASB111276
CRANKCASE
Separating the crankcase
Order Part name Q’ty Remarks
Engine Refer to “ENGINE REMOVAL” on page 5-1.
PistonRefer to “CYLINDER AND PISTON” on page
5-33.
BalancerRefer to “OIL PUMP AND BALANCER
GEAR” on page 5-55.
Kick shaft assembly Refer to “KICKSTATER” on page 5-47.
Segment Refer to “SHIFT SHAFT” on page 5-50.
Stator Refer to “AC MAGNETO” on page 5-61.
1 Timing chain guide (exhaust side) 1
2 Timing chain guide stopper plate 1
3 Timing chain 1
4 Bolt [L = 45 mm (1.77 in)] 6
5 Bolt [L = 65 mm (2.56 in)] 4
6 Bolt [L = 75 mm (2.95 in)] 2
7 Right crankcase 1
8 Left crankcase 1
9 Dowel pin 2
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
5-65
10 Crankshaft 1
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