YAMAHA WR 450F 2016 Owners Manual

CAMSHAFT
6-14
EAS2GC1239CHECKING THE CAMSHAFT
1. Check:• Camshaft lobes
Blue discoloration/pitting/scratches  Re-
place the camshaft.
2. Measure:
• Camshaft lobe dimensions “A” and “B”Out of specification  Replace the cam-
shaft. 3. Measure:
• Camshaft runout
Out of specification  Replace.
4. Measure: • Camshaft-journal-to-camshaft-cap clear-ance
Out of specification  Measure the cam-
shaft journal diameter.
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a. Install the camshaft into the cylinder head.
b. Position a strip of Plastigauge® “1” onto the camshaft journal as shown.
Camshaft lobe dimensions
Lobe height (Intake)37.630–37.730 mm (1.4815–
1.4854 in)
Limit 37.530 mm (1.4776 in)
Base circle diameter (intake) 27.950–28.050 mm (1.1004–
1.1043 in)
Limit 27.850 mm (1.0965 in)
Lobe height (Exhaust) 33.870–33.970 mm (1.3335–
1.3374 in)
Limit 33.770 mm (1.3295 in)
Base circle diameter (Exhaust) 24.711–24.811 mm (0.9729–
0.9768 in)
Limit 24.611 mm (0.9689 in)
1
2
3
Camshaft runout limit 0.030 mm (0.0012 in)
Camshaft-journal-to-camshaft-
cap clearance 0.028–0.062 mm (0.0011–0.0024
in)
1

CAMSHAFT
6-15
c. Install the dowel pins and the camshaft caps.
TIP
• Tighten the camshaft cap bolts in a crisscross pattern from innermost to outer caps.
• Do not turn the camshaft when measuring the
camshaft journal-to-camshaft cap clearance.
d. Remove the camshaft caps and then mea- sure the width of the Plastigauge® “1”.
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5. Measure:• Camshaft journal diameter “a”Out of specification  Replace the cam-
shaft.
Within specification  Replace the cylinder
head and the camshaft caps as a set.
EAS2GC1240CHECKING THE TIMING CHAIN AND CAM-
SHAFT SPROCKET
1. Check: • Timing chain “1”
Damage/stiffness  Replace the timing
chain and camshaft as a set. 2. Check:
• Camshaft sprocketMore than 1/4 tooth wear “a”  Replace the
camshaft and the timing chain as a set.
EAS2GC1241CHECKING THE TIMING CHAIN TENSION-
ERS
1. Check: • Timing chain tensioner
Crack/damage  Replace.
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a. While pressing the tensioner rod lightly with
your fingers, use a thin screwdriver “1” to
wind the tensioner rod up fully clockwise.
b. When releasing the screwdriver by pressing lightly with your fingers, make sure that the
tensioner rod will come out smoothly.
c. If not, replace the tensioner assembly.
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Camshaft cap bolts 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Camshaft journal diameter 21.959–21.972 mm (0.8645–
0.8650 in)
T R..
1
a. 1/4 tooth
b. Correct
1. Timing chain roller
2. Camshaft sprocket
a
b 1
2

CAMSHAFT
6-16
EAS2GC1242CHECKING THE DECOMPRESSION SYS-
TEM
1. Check:• Decompression system
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a. Check that the decompressor cam “1”
moves smoothly.
b. Check that the decompressor lever pin “2” projects from the camshaft.
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EAS2GC1243INSTALLING THE CAMSHAFTS
1. Install:• Exhaust camshaft “1”
• Intake camshaft “2”
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a. Turn the crankshaft counterclockwise with a
wrench.
TIP
• Apply molybdenum disulfide oil to the cam-shafts.
• Apply the engine oil on the decompression
system.
b. Align the top dead center (TDC) mark “a” on the rotor with the alignment mark “b” on the
crankcase cover. c. Fit the timing chain “3” onto both camshaft
sprockets and install the camshafts on the
cylinder head.
TIP
Make sure that the alignment mark “c” on the
exhaust camshaft sprocket and the alignment
mark “d” on the intake camshaft sprocket are
aligned with the edge of the cylinder head.
ECA
NOTICE
Do not turn the crankshaft during the cam-
shaft installation. Damage or improper
valve timing will result.
d. Install the clips, the camshaft caps and the bolts (camshaft cap).
TIP
• Before installing the clips, cover the cylinder head with a clean cloth to prevent the clips
from coming off into the cylinder head cavity.
• Apply the engine oil to the threads and con- tact surfaces.
• Tighten the bolts to the specified torque in two or three steps in the proper tightening se-
quence as shown.
ECA
NOTICE
The bolts (camshaft cap) must be tightened
evenly, or damage to the cylinder head,
camshaft caps, and camshaft will result.
1
2
Bolt (camshaft cap)
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
ab
c
3
d
T R..

CAMSHAFT
6-17
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2. Install:• Timing chain tensioner
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a. While pressing the tensioner rod lightly with
your fingers, use a thin screwdriver to wind
the tensioner rod up fully clockwise.
b. With the tensioner rod fully wound and the chain tensioner UP mark “a” facing upward,
install the gasket “1”, the timing chain ten-
sioner “2”, and the gasket “3”, and tighten
the bolt “4”.
c. Release the screwdriver, check that the ten- sioner rod comes out smoothly, and tighten
the gasket “5” and the cap bolt “6”.
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3. Turn:• Crankshaft
Counterclockwise several turns.
4. Check: • Top dead center (TDC) mark on the rotor
Align with the crankcase alignment mark.
• Camshaft match marks Align with the cylinder head surface.
Out of alignment  Adjust.
5. Install: • Timing chain guide (top side) “1”
• Cylinder head cover gasket “2”
• Cylinder head cover “3”
• Bolt (cylinder head cover) “4”
TIP
Before installation, apply the sealant to the cyl-
inder head cover gasket.
6. Install:• Cylinder head breather hose
• Spark plug
Bolt (timing chain tensioner)
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Tensioner cap bolt 6 Nm (0.6 m·kgf, 4.3 ft·lbf)
3 48
7
1 5
26
E
T R..
T R..
Bolt (cylinder head cover)
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Yamaha bond No. 1215 90890-85505
(Three bond No.1215®)
Spark plug 13 Nm (1.3m·kgf, 9.4 ft·lbf)
6
5
T R..
4
4
4 3
2 1
T R..

CYLINDER HEAD
6-18
EAS2GC1244
CYLINDER HEAD
Removing the cylinder head
OrderPart name Q’tyRemarks
Refer to “INSTALLING THE CYLINDER
HEAD” on page 6-21.
Seat Refer to “GENERAL CHASSIS” on page 5-1.
Side cover (left/right) Refer to “GENERAL CHASSIS” on page 5-1.
Air scoop (left / right) Refer to “GENERAL CHASSIS” on page 5-1.
Fuel tank Refer to “FUEL TANK” on page 8-1.
Exhaust pipe and silencer Refer to “ENGINE REMOVAL” on page 6-1.
Radiator hose Disconnect.
Coolant temperature sens or coupler Disconnect.
Throttle body Refer to “THROTTLE BODY” on page 8-7.
Camshaft Refer to “CAMSHAFT” on page 6-11.
Upper engine bracket Refer to “ENGINE REMOVAL” on page 6-1.
1 Bolt (cylinder head) 2
2 Engine ground sub-lead 1
3 Bolt (cylinder head) 4
4 Cylinder head 1
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
*

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

CYLINDER HEAD
6-20
EAS2GC1245REMOVING THE CYLINDER HEAD
1. Remove:• Cylinder head bolts
TIP
• Loosen the bolts in the proper sequence as shown.
• Loosen each bolt 1/2 of a turn at a time. After
fully loosening all the bolts, remove them.
•M6  35 mm (1.38 in): “1” – “2”
• M10  149 mm (5.87 in): “3” – “6”
EAS2GC1246CHECKING THE TIMING CHAIN GUIDE (IN-
TAKE SIDE)
1. Check:
• Timing chain guide (intake side)Damage/wear  Replace.
EAS2GC1247CHECKING THE CYLINDER HEAD
1. Eliminate:
• Combustion chamber carbon deposits
TIP
Use a rounded scraper, not a sharp instrument,
in order not to damage or scratch the spark
plug bore threads. 2. Check:
• Cylinder head
Damage/scratches  Replace.
TIP
When replacing the cylinder head, replace also
the valve.
Refer to “CHECKING THE VALVE SEATS” on
page 6-26.
• Cylinder head coolant passagesMineral deposits/rust  Eliminate.
3. Measure: • Cylinder head warpage
Out of specification  Resurface the cylin-
der head.
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a. Place a straightedge and a thickness gauge across the cylinder head.
b. Measure the warpage.
c. If the limit is exceeded, resurface the cylin-
der head as follows.
d. Place a 400–600 grit wet sandpaper on a
surface plate, and resurface the cylinder
head using a figure-eight sanding pattern.
TIP
To ensure an even surface, turn the cylinder
head several times.
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61
2
35
4
x2 x4
FWD
Warpage limit
0.05 mm (0.0020 in)

CYLINDER HEAD
6-21
EAS2GC1248INSTALLING THE CYLINDER HEAD
1. Install:• Timing chain guide (intake side) “1”
• Dowel pins “2”
• Cylinder head gasket
• Dowel head “4”
TIP
While pulling up the timing chain, install the tim-
ing chain guide (intake side) and the cylinder
head.
2. Install:• Washer “1”
• Cylinder head bolt “2”
• Engine ground sub-lead “3”
• Cylinder head bolt “4”
TIP
Tighten the bolts using the following procedure.
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a. Wash the threads and contact surfaces of the bolts, the contact surfaces of the wash-
ers, the contact surface of the cylinder head,
and the threads of the crankcase.
b. Apply molybdenum disulfide grease to the threads and contact surfaces of the bolts
and to both contact surfaces of the washers
“1”.
c. Install the washers and the bolts.
d. Tighten the bolts to the specified torque in
two or three steps in the proper tightening
sequence as shown. e. Remove the bolts.
f. Again apply molybdenum disulfide grease to
the threads and contact surfaces of the bolts
and to both contact surfaces of the washers.
g. Retighten the bolts.
TIP
Tighten the bolts to the specified torque in two
or three steps in the proper tightening se-
quence as shown.
h. Put a mark on the corner “1” of the bolt (cyl- inder head) and the cylinder head “2” as
shown.
New
1 2
2
4
3
1
3 4
2
2
4
Bolt “1”–“4”
1st
30 Nm (3.0 m·kgf, 22 ft·lbf)
Bolt “1”–“4” 2nd
20 Nm (2.0 m·kgf, 14 ft·lbf)
T R..
15
6
42
3
FWD
x2 x4
T R..
1
2

CYLINDER HEAD
6-22
i. Retighten the cylinder head mounting bolts
150° in the proper tightening sequence.
TIP
Tighten the bolts in two steps (90° and 60°) to
reach the specified angle in the proper tighten-
ing sequence.
j. Tighten the bolts to the specified torque.
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Bolt “1”–“4” Final
Specified angle 150°
Bolt “5”, “6” 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
T R..
T R..

VALVES AND VALVE SPRINGS
6-23
EAS2GC1249
VALVES AND VALVE SPRINGS
Removing the valves and valve springs
OrderPart name Q’tyRemarks
Cylinder head Refer to “CYLINDER HEAD” on page 6-18.
1 Valve lifter 4
2 Adjusting pad 4
3 Valve cotter 8
4 Valve spring retainer 4
5 Valve spring 4
6 Valve stem seal 4
7 Valve spring seat 4
8 Intake valve 2
9 Exhaust valve 2
For installation, reverse the removal proce-
dure.