Yamaha 2011 WR250FA Owner's Service Manual page 154

CHECKING THE CAMSHAFT
1. Inspect:
• Cam lobe
Pitting/scratches/blue discoloration → Re-
place.
2. Measure:
• Cam lobe length "a" and "b"
Out of specification → Replace.
Cam lobes length:
Intake "a":
29.65–29.75 mm (1.1673–1.1713
in)
<Limit>:
29.55 mm (1.1634 in)
Intake "b":
22.45–22.55 mm (0.8839–0.8878
in)
<Limit>:
22.35 mm (0.8799 in)
Exhaust "a":
30.399–30.499 mm (1.1968–
1.2007 in)
<Limit>:
30.299 mm (1.1929 in)
Exhaust "b":
22.45–22.55 mm (0.8839–0.8878
in)
<Limit>:
22.35 mm (0.8799 in)
3. Measure:
• Runout (camshaft)
Out of specification → Replace.
Runout (camshaft):
Less than 0.03 mm (0.0012 in)
4. Measure:
• Camshaft-to-cap clearance
Out of specification → Measure camshaft
outside diameter.
Camshaft-to-cap clearance:
0.028–0.062 mm (0.0011–0.0024 in)
<Limit>:0.08 mm (0.003 in)
Measurement steps:
a. Install the camshaft onto the cylinder head.
b. Position a strip of Plastigauge
camshaft.
c. Install the clip, dowel pins and camshaft
caps.
Bolt (camshaft cap):
10 Nm (1.0 m•kg, 7.2 ft•lb)
• Tighten the bolts (camshaft cap) in a criss-
cross pattern from innermost to outer caps.
• Do not turn the camshaft when measuring
clearance with the Plastigauge
5-21
CAMSHAFTS
®
"1" onto the
®
.