2016 YAMAHA WR 450F check oil

CYLINDER HEAD
6-19
5 Cylinder head gasket1
6 Timing chain guide (intake side) 1
7 Oil check bolt 2
8 Oil passage plug 1
For installation, reverse the removal proce-
dure.
Removing the cylinder head
Order Part name Q’tyRemarks
8
6
7
7
10 Nm (1.0 m kgf, 7.2 ft Ibf)T.R.
10 Nm (1.0 m kgf, 7.2 ft Ibf)T.R.
15 Nm (1.5 m kgf, 11 ft Ibf)T.R.
*
20 Nm (2.0 mkgf, 14 ftIbf)T.
R.
30 Nm (3.0 mkgf, 22 ftIbf)
2
4 3
3
5
1
1

VALVES AND VALVE SPRINGS
6-29
EAS2GC1254CHECKING THE VALVE LIFTERS
1. Check:• Valve lifter
Damage/scratches  Replace the valve lift-
ers and cylinder head.
EAS2GC1255INSTALLING THE VALVES
1. Clean: • Valve stem end
2. Lubricate: • Valve stem “1”
• Valve stem seal “2” 3. Install:
• Spring seat “1”
• Valve stem seal “2”
•Valve “3”
• Valve spring “4”
• Valve spring retainer “5”
(to the cylinder head)
TIP
• Make sure each valve is installed in its original place.
• Install the valve springs with the larger pitch
“a” facing up.
4. Install: • Valve cotter “1”
TIP
Install the valve cotters by compressing the
valve spring with the valve spring compressor
“2” and the valve spring compressor adapter
“3”.
Recommended lubricant Molybdenum disulfide oil
b. Smaller pitch
Valve spring compressor90890-04019
Valve spring compressor YM-04019
Valve spring compressor attach-
ment 90890-04108
Valve spring compressor adapter
22 mm YM-04108
New

CYLINDER AND PISTON
6-32
EAS2GC1257REMOVING THE PISTON
1. Remove:• Piston pin clips “1”
• Piston pin “2”
• Piston “3”
ECA13810
NOTICE
Do not use a hammer to drive the piston pin
out.
TIP
• Before removing the piston pin clip, cover the crankcase opening with a cloth to prevent the
piston pin clip from falling into the crankcase.
• Before removing the piston pin, deburr the piston pin clip’s groove and the piston pin’s
bore area. If the piston pin groove is deburred
and the piston pin is still difficult to remove,
use the piston pin puller set “4”.
2. Remove: • Top ring
• 2nd ring
• Oil ring
TIP
When removing a piston ring, open the end gap
with your fingers and lift the opposite end gap
of the piston ring over the piston crown.
EAS2GC1258CHECKING THE CYLINDER AND PISTON
1. Check:• Piston wall (Sidewall)
• Cylinder wall
Vertical scratches  Replace the cylinder,
and replace the piston and piston rings as a
set.
2. Measure: • Piston-to-cylinder clearance
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Measure the cylinder bore with the cylinder
bore gauge.
TIP
Measure cylinder bore by taking side-to-side
and front-to-back measurements of the cylin-
der.
Piston pin puller set
90890-01304
Piston pin puller YU-01304
1
Bore 97.000–97.010 mm (3.8189–
3.8193 in)
Taper limit 0.050 mm (0.0020 in)
Out of round limit 0.050 mm (0.0020 in)
Cylinder bore = maximum of D
1, D2, D3, D4,
D
5, D6
Taper limit (front-to-back) = maximum differ-
ence between D
1, D3, D5Taper limit (side-to-side) = maximum differ-
ence between D
2, D4, D6
Out of round limit (top) = difference between
D
1, D2Out of round limit (middle) = difference be-
tween D
3, D4Out of round limit (bottom) = difference be-
tween D
5, D6

CYLINDER AND PISTON
6-34
3. Measure:• Piston ring end gapOut of specification  Replace the piston
ring.
TIP
The oil ring expander’s end gap cannot be
measured. If the oil ring ra il’s gap is excessive,
replace all three oil rings.
EAS2GC1260CHECKING THE PISTON PIN
1. Check:
• Piston pinBlue discoloration/grooves  Replace the
piston pin and then check the lubrication
system.
2. Measure: • Piston pin outside diameter “a”
Out of specification  Replace the piston
pin. 3. Measure:
• Piston pin bore inside diameter “b”Out of specification  Replace the piston.
EAS2GC1261INSTALLING THE PISTON AND CYLINDER
1. Install:
• Oil ring expander “1”
• Lower oil ring rail “2”
• Upper oil ring rail “3”
• 2nd ring “4”
• Top ring “5”
TIP
Be sure to install the piston rings so that the
manufacturer’s marks or numbers face up.
Piston ring
Top ring
End gap (installed)0.20–0.30 mm (0.0079–0.0118 in)
Limit 0.55 mm (0.0217 in)
2nd ring End gap (installed)0.35–0.50 mm (0.0138–0.0197 in)
Limit 0.85 mm (0.0335 in)
Oil ring End gap (installed)0.20–0.50 mm (0.0079–0.0197 in)
Piston pin outside diameter 17.991–18.000 mm (0.7083–
0.7087 in)
Limit 17.971 mm (0.7075 in)
Piston pin bore inside diameter 18.004–18.015 mm (0.7088–
0.7093 in)
Limit 18.045 mm (0.7104 in)
b

ELECTRIC STARTER
6-38
EAS2GC1263CHECKING THE STARTER MOTOR
1. Check:•CommutatorDirt  Clean with 600 grit sandpaper.
2. Measure: • Commutator diameter “a”Out of specification  Replace the starter
motor.
3. Measure: • Mica undercut “a”Out of specification  Scrape the mica to
the proper measurement with a hacksaw
blade that has been grounded to fit the com-
mutator.
TIP
The mica of the commutator must be undercut
to ensure proper operation of the commutator.
4. Measure: • Armature assembly resistances (commuta-
tor and insulation)
Out of specification  Replace the starter
motor.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Measure the armature assembly resistanc-
es with the pocket tester.
b. If any resistance is out of specification, re- place the starter motor.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
5. Measure:• Brush length “a”Out of specification  Replace the brush
set.
6. Measure: • Brush spring force
Out of specification  Replace the brush
set.
Limit
16.6 mm (0.65 in)
Mica undercut (depth) 1.50 mm (0.06 in)
Pocket tester90890-03112
Analog pocket tester YU-03112-C
Armature coil Commutator resistance “1” 0.0117–0.0143 
Insulation resistance “2” Above 1 M 
Limit 3.50 mm (0.14 in)
Brush spring force 3.92–5.88 N (400–600 gf, 14.11–
21.17 oz)

ELECTRIC STARTER
6-39
7. Check:• Gear teethDamage/wear  Replace the starter motor.
8. Check: • Oil sealDamage/wear  Replace the defective part
(s).
EAS2GC1264ASSEMBLING THE STARTER MOTOR
1. Install: • Brush spring “1”
• Brush “2”
TIP
Align the corner of brush terminal “a” with
groove “b” and fit them together.
2. Install:• Armature assembly “1”
Install while holding down the brush using a
thin screw driver.
ECA
NOTICE
Be careful not to damage the brush during
installation.
3. Install:• O-ring “1”
• Starter motor yoke “2”
TIP
• Install the starter motor yoke with its groove “a” facing starter motor rear cover.
• Align the match mark “b” on the starter motor
yoke with the match mark “c” on the starter
motor rear cover. 4. Install:
• Circlip “1”
•Plain washer “2”
• O-ring “3”
• Washer (starter motor front cover) “4”
• Starter motor front cover “5”
TIP
• For installation, align the projections on the
washer with the slots in the front cover.
• Align the match mark “a” on the starter motor yoke with the match mark “b” on the starter
motor front cover.
5. Install: •Bolt “1”
• O-ring “2”
TIP
Apply the lithium-soap-based grease on the O-
ring.
a
b1
1
2
2
New
c b
a
1 2
New
a
12
3
b
45
New
2
1 1

CLUTCH
6-46
EAS2GC1276CHECKING THE PRIMARY DRIVEN GEAR
1. Check:• Primary driven gearDamage/wear  Replace the primary drive
and primary driven gears as a set.
Excessive noise during operation  Re-
place the primary drive and primary driven
gears as a set.
EAS2GC1277INSTALLING THE OIL SEAL
1. Install: • Oil seal “1”
• Washer “2”
• Circlip “3”
TIP
• Apply the lithium-soap-based grease on the
oil seal lip.
• Install the oil seal in parallel with its manufac-
ture's marks or numbers facing inward.
EAS2GC1278INSTALLING THE RIGHT CRANKCASE
COVER
1. Install: • Dowel pin “1”
• O-rings “2”
• Collar “3”
• Gasket “4”
TIP
Apply the lithium-soap-based grease on the O-
ring.
2. Install:
• Right crankcase cover “1” • Right crankcase cover bolt “2”
TIP
• Apply the engine oil on the impeller shaft end.
• When installing the crankcase cover onto the
crankcase, make sure that the impeller shaft
end “3” aligns with the balancer end slot “4”.
• Tighten the right crankcase cover bolts in
stages and in a crisscross pattern.
EAS2GC1279INSTALLING THE CLUTCH
1. Install:
• Push lever shaft “1”
TIP
• Apply the lithium-soap-based grease on the oil seal lip.
• Before installation, apply the engine oil to the
push lever shaft sliding surface.
New
New
3
2
1
LS
New
New
1
1
4
2
New
New
3
LS
Right crankcase cover bolt10 Nm (1.0 m·kgf, 7.2 ft·lbf)
T R..
1 2
1

KICKSTATER
6-51
EAS2GC1282REMOVING THE KICK SHAFT ASSEMBLY
1. Remove:• Kick shaft assembly “1”
TIP
Unhook the torsion spring “2” from the hole “a”
in the crankcase.
EAS2GC1283CHECKING THE KICK SHAFT AND RATCH-
ET WHEEL
1. Check:• Ratchet wheel “1” smooth movementUnsmooth movement  Replace.
• Kick shaft “2” Wear/damage  Replace the kick shaft as-
sembly.
• Spring “3” Broken  Replace.
EAS2GC1284CHECKING THE KICK GEAR, KICK IDLE
GEAR AND RATCHET WHEEL
1. Check:
• Kick gear “1”
Wear/damage  Replace the kick shaft as-
sembly.
• Kick idle gear “2”
• Ratchet wheel “3”
• Gear teeth “a”
• Ratchet teeth “b”
Wear/damage  Replace.
EAS2GC1285INSTALLING THE KICK SHAFT ASSEMBLY
1. Install:
• Kick gear “1”
• Washer “2”
• Circlip “3”
• Ratchet wheel “4”
• Spring “5”
• Washer “6”
• Circlip “7”
(to the kick shaft “8”)
TIP
• Apply molybdenum disulfide oil to the inner circumferences of the kick gear and ratchet
wheel.
• Align the punch mark “a” on the ratchet wheel
with the punch mark “b” on the kick shaft.
2. Install: • Torsion spring “1”
(to the kick shaft “2”)
TIP
Make sure the stopper “a” of the torsion spring
fits into the hole “b” on the kick shaft.
3 1
2
a
b 3
12
New
New