Yamaha YW50P Service Manual page 79

OV'.°OE..EAO. OV'..OE. A°O P.STO. I E"O I o =1
PISTON R I N G S I N S P E C T I O N
1. Measure:
• Side clearance
O u t of s p e c i f i c a t i o n - - > R e p l a c e p i s t o n
a n d / o r rings.
Use a feeler g a u g e ( ~
S t a n d a r d m i t Li
T o p ring 0 . 0 3 ~ 0 . 0 5 m m 0.1 m m
(0.0012 ~ 0.002 in) (0.0039 in)
2nd ring 0 . 0 3 - 0 . 0 5 m m 0.1 m m
(0.0012 ~ 0.002 in) (0.0039 in)
2. Install:
• Piston ring
Into the c y l i n d e r
Push t h e ring w i t h the piston c r o w n .
L
.
Measure:
• End gap
Out of specification-->Replace r i n g s as
a set.
Use a feeler g a u g e (~.
Stand rd Li it
a
m
T o p ring 0 . 1 5 - 0.35 m m 0 . 6 r a m
(0.005 ~ 0.01 in) (0.02 in)
2nd ring 0 . 1 5 ~ 0 . 3 5 m m 0 . 6 r a m
(0.005 ~ 0.01 in) (0.02 in)
( ~ M e a s u r i n g Point 20 m m ( 0 . 7 9 in)
PISTON PIN A N D P I S T O N PIN B E A R I N G
1. Inspect:
• Piston pin
B l u e
discoloration/Groove-->Replace,
t h e n inspect l u b r i c a t i o n s y s t e m .
4-7