Yamaha YZ450FX 2019 Owner's Service Manual page 216

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 contact
surfaces.
• Tighten the bolts to the specified torque in two
or three steps in the proper tightening se-
quence as shown.
ECA24630
NOTICE
The bolts (camshaft cap) must be tightened
evenly, or damage to the cylinder head, cam-
shaft caps, and camshaft will result.
3 3
1 1 1 2 2
E
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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".
Bolt (timing chain tensioner)
10 N·m (1.0 kgf·m, 7.4 lb·ft)
4 4 8 8 7 7
6 6 5 5
5-17
a a
1 1
4 4
c. Release the screwdriver, check that the ten-
sioner rod comes out smoothly, and tighten
the gasket "5" and the cap bolt "6".
Tensioner cap bolt
6 N·m (0.6 kgf·m, 4.4 lb·ft)
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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"
Bolt (cylinder head cover)
10 N·m (1.0 kgf·m, 7.4 lb·ft)
TIP
• Before installation, apply the sealant to the cyl-
inder head cover gasket.
• After installing the cylinder head cover gasket
"2" to the cylinder head cover, cut off the "a"
section.
CAMSHAFT
3 3
4 4
2 2 2
5 5
6 6 6
New