Checking The Camshaft - Yamaha YZ450FX 2019 Owner's Service Manual

from falling into the crankcase.
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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:
• Camshaft-journal-to-camshaft-cap clearance
Out of specification  Measure the camshaft
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.
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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CAMSHAFT
Camshaft-journal-to-camshaft-
cap clearance
0.028–0.062 mm (0.0011–0.0024
in)
Camshaft cap bolt
10 N·m (1.0 kgf·m, 7.4 lb·ft)
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