Yamaha 2012 Grizzly 300 Service Manual page 137

VALVES AND VALVE SPRINGS
EBS00240
CHECKING THE VALVES AND VALVE
SPRINGS
1. Measure:
• stem-to-guide clearance
Stem-to-guide clearance =
valve guide inside diameter
valve stem diameter
Out of specification
head ass'y.
2. Check:
• valve face
Pitting/wear
• valve stem end
Mushroom shape or diameter larger than
the body of the stem
3. Measure:
• margin thickness
Out of specification
4-17
ENG
b
→
Replace the cylinder
Stem-to-guide clearance
Intake
0.010 ~ 0.037 mm
(0.0004 ~ 0.0015 in)
<Limit>: 0.08 mm (0.0031 in)
Exhaust
0.025 ~ 0.052 mm
(0.0010 ~ 0.0020 in)
<Limit>: 0.10 mm (0.0039 in)
→
Grind the face.
→
Replace.
a
→
Replace.
Margin thickness
Intake
0.50 ~ 0.90 mm
(0.0197 ~ 0.0354 in)
Exhaust
0 .80 ~ 1.20 mm
(0.0315 ~ 0.0472 in)
–
a