Checking The Timing Chain And Camshaft Sprocket - Yamaha YZ450FP 2023 Owner's Service Manual

place the camshaft.
2. Measure:
• Camshaft lobe dimensions "A"
Out of specification  Replace the camshaft.
Camshaft lobe dimensions
Lobe height limit (Intake)
38.030 mm (1.4972 in)
Lobe height limit (Exhaust)
34.170 mm (1.3453 in)
3. Measure:
• Camshaft-journal-to-camshaft-cap clearance
Out of specification  Measure the camshaft
journal diameter.
Camshaft-journal-to-camshaft-
cap clearance
0.028–0.062 mm (0.0011–0.0024
in)
a. Install the camshaft into the cylinder head.
b. Position a strip of Plastigauge® "1" onto
the camshaft journal as shown.
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.
Camshaft cap bolt
10 N·m (1.0 kgf·m, 7.4 lb·ft)
d. Remove the camshaft caps and then mea-
sure the width of the Plastigauge® "1".
4. Measure:
• Camshaft journal diameter "a"
Out of specification  Replace the camshaft.
Within specification  Replace the cylinder
head and the camshaft caps as a set.
EAM30082
CHECKING THE TIMING CHAIN AND
CAMSHAFT SPROCKET
1. Check:
1
• Timing chain "1"
Damage/stiffness  Replace the timing
chain and camshaft as a set.
2. Check:
• Camshaft sprocket
More than 1/4 tooth wear "a"  Replace the
camshaft and the timing chain as a set.
5-13
CAMSHAFT
1 1 1
Camshaft journal diameter
22.002–22.015 mm (0.8662–
0.8667 in)