Yamaha YZ 2017 Series, Owner'S Service Manual

Page: 216 / 410

CAMSHAFT
5-15
EASB29B212 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.
3. Measure:
• Camshaft runout
Out of specification

Replace.
4. Measure:
• Camshaft-journal-to-camshaft-cap clear-
ance
Out of specification

Measure the cam-
shaft journal diameter.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Install the camshaft into the cylinder head.
b. Position a strip of Plastigauge® “1” onto the
camshaft journal as shown.
Camshaft lobe dimensions
Lobe height (Intake)
31.830–31.930 mm (1.2531–
1.2571 in)
Limit
31.730 mm (1.2492 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)
33.870–33.970 mm (1.3335–
1.3374 in)
Limit
33.770 mm (1.3295 in)
Base circle diameter (Exhaust)
25.211–25.311 mm (0.9926–
0.9965 in)
Limit
25.111 mm (0.9886 in)
1
2
3
Camshaft runout limit
0.030 mm (0.0012 in)
Camshaft-journal-to-camshaft-
cap clearance
0.028–0.062 mm (0.0011–0.0024
in)
1