Piston Rings Inspection; Piston Pin And Piston Pin Bearing - Yamaha YW50AP Service Manual

CYLINDER HEAD, CYLINDER AND PISTON
a

PISTON RINGS INSPECTION

1. Measure:
8 Side clearance
Out of specification→Replace piston
and/or rings.
Use a feeler gauge 1
Standard
Top ring 0.03 ~ 0.05 mm
(0.0012 ~ 0.002 in)
2nd ring 0.03 ~ 0.05 mm
(0.0012 ~ 0.002 in)
2. Install:
8 Piston ring
Into the cylinder
Push the ring with the piston crown.
3. Measure:
8 End gap
Out of specification→Replace rings as
a set.
Use a feeler gauge 1.
Standard
Top ring 0.15 ~ 0.35 mm
(0.005 ~ 0.01 in)
2nd ring 0.15 ~ 0.35 mm
(0.005 ~ 0.01 in)
a Measuring Point 20 mm(0.79 in)

PISTON PIN AND PISTON PIN BEARING

1. Inspect:
8 Piston pin
Blue discoloration/Groove→Replace,
then inspect lubrication system.
4-7
ENG
Limit
0.1 mm
(0.0039 in)
0.1 mm
(0.0039 in)
Limit
0.6 mm
(0.02 in)
0.6 mm
(0.02 in)