Checking The Camshaft - Yamaha YZ450F 2020 Owner's Service Manual

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EAM30081

CHECKING THE CAMSHAFT

1. Check:
• Camshaft lobe
Blue discoloration/pitting/scratches  Re-
place the camshaft.
2. Measure:
• Camshaft lobe dimensions "A"
Out of specification  Replace the camshaft.
Camshaft lobe dimensions
Lobe height (Intake)
38.130–38.230 mm (1.5012–
1.5051 in)
Limit
38.030 mm (1.4972 in)
Lobe height (Exhaust)
34.270–34.370 mm (1.3492–
1.3531 in)
Limit
34.170 mm (1.3453 in)
3. Measure:
• Camshaft runout
Out of specification  Replace.
Camshaft runout limit
0.030 mm (0.0012 in)
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4. Measure:
TIP
• Tighten the camshaft cap bolts in a crisscross
• Do not turn the camshaft when measuring the
5-16
• 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.
pattern from innermost to outer caps.
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".
CAMSHAFT
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