Checking The Camshaft - Yamaha YZ 2016 Series Owner's Service Manual

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EASB296213

CHECKING 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.
Camshaft lobe dimensions
Lobe height (Intake)
31.730–31.830 mm (1.2492–
1.2531 in)
Limit
31.630 mm (1.2453 in)
Base circle diameter (Intake)
22.450–22.550 mm (0.8839–
0.8878 in)
Limit
22.350 mm (0.8799 in)
Lobe height (Exhaust)
33.370–33.470 mm (1.3138–
1.3177 in)
Limit
33.270 mm (1.3098 in)
Base circle diameter (Exhaust)
25.211–25.311 mm (0.9926–
0.9965 in)
Limit
25.111 mm (0.9886 in)
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3. Measure:
• Camshaft runout
Out of specification  Replace.
Camshaft runout limit
4. Measure:
• Camshaft-journal-to-camshaft-cap clear-
ance
Out of specification  Measure the cam-
shaft journal diameter.
Camshaft-journal-to-camshaft-
cap clearance
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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.
5-15
CAMSHAFT
0.030 mm (0.0012 in)
0.028–0.062 mm (0.0011–0.0024
in)
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