2014 YAMAHA YZ450F engine

SHIFT SHAFT
5-52
EAS1SL1260INSTALLING THE STOPPER LEVER
1. Install:
• Torsion spring “1”
• Collar “2”
• Stopper lever “3”
• Bolt (stopper lever) “4”
EAS1SL1261INSTALLING THE SEGMENT
1. Install:
• Segment “1”
• Segment bolt
TIP
• Align the notch “a” on the segment with the
pin “b” on the shift cam.
• With the stopper lever pushed down, install
the segment.
ECA1DX1022
NOTICE
If the segment gets an impact, it may be
damaged. Take care not to give an impact to
it when tightening the bolt.
EAS1SL1262
INSTALLING THE SHIFT GUIDE AND SHIFT
LEVER ASSEMBLY
1. Install:
• Spring “1”
• Pawl pin “2”
•Pawl “3”
(to the shift lever “4”)
TIP
Apply the engine oil on the spring, pawl pin and
pawl.
2. Install:
• Shift lever assembly “1”
(to the shift guide “2”)
3. Install:
• Shift lever assembly “1”
• Shift guide “2”
TIP
• The shift lever assembly is installed at the
same time as the shift guide.
• Apply the engine oil on the segment bolt shaft.
Bolt (stopper lever)
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
LOCTITE®
Segment bolt
30 Nm (3.0 m·kgf, 22 ft·lbf)
T R..
42
13
LT
T R..
1
2
1 2

SHIFT SHAFT
5-53
4. Tighten:
• Shift guide bolt “1”
EAS1SL1263INSTALLING THE SHIFT SHAFT
1. Install:
• Roller “1”
• Shift shaft spring “2” (to shift shaft)
• Collar “3” (to shift shaft)
• Shift shaft “4”
TIP
Apply the engine oil on the roller and shift shaft.
2. Install:
• Oil seal
EAS1SL1264
INSTALLING THE SHIFT PEDAL
1. Install:
• Shift pedal “1”
• Shift pedal bolt “2”
TIP
Align the punch mark “a” on the shift shaft with
the punch mark “b” in the shift pedal.
Shift guide bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
LOCTITE®
T R..
1 1
LT
E
E
1
23
4
New
Shift pedal bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)T R..
a
12b

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

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
5-65
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

TRANSMISSION
5-70
EAS1SL1288
TRANSMISSION
Removing the transmission, shift drum assembly, and shift forks
OrderPart nameQ’tyRemarks
EngineRefer to “ENGINE REMOVAL” on page 5-1.
CrankcaseSeparate.Refer to “CRANKCASE” on page 5-62.
1Main axle1
2Drive axle1
3Long shift fork guide bar1
4Short shift fork guide bar1
5Spring4
6Shift cam1
7Shift fork 3 (R)1
8Shift fork 2 (C)1
9Shift fork 1 (L)1
10Collars1
For installation, reverse the removal proce-dure.
2
10
1
53
4 578
69
M
M
M
M
M
EE
E
E
LS
New