Piston Pin And Piston Pin Bearing - Yamaha YQ50 Service Manual

a
b
INSPECTION AND REPAIR
Top
ring
2nd
ring
@ Measuring Point 20 mm (0.8 in)

PISTON PIN AND PISTON PIN BEARING

1. Inspect :
• Piston pin
Blue discoloration/Groove © Replace, then
inspect lubrication system.
2. Measure :
• Outside diameter (piston pin)
Out of specification © Replace.
307009
3. Measure :
• Piston pin-to-piston clearance
Out of specification © Replace piston.
Piston pin-to-piston clearance =
Bore (piston pin) b -
Outside diameter (piston pin) a
307010
4. Inspect :
• Bearing (piston pin)
Pitting/Damage © Replace
307011
4-14
ENG
Standard
0.15 ~ 0.30 mm
(0.005 ~ 0.011 in)
0.15 ~ 0.30 mm
(0.005 ~ 0.011 in)
Outside diameter (piston pin) :
9.996 ~ 10.000 mm
(0.3935 ~ 0.3937 in)
Piston pin-to-piston clearance :
0.004 ~ 0.019 mm
(0.0002 ~ 0.0008 in)
<Limit : 0.07 mm (0.028 in)>
Limit
0.70 mm
(0.028 in)
0.70 mm
(0.028 in)