Yamaha 4TX-AE1, Service Manual

Page: 149 / 332

4-25
CYLINDER AND PISTON
ENG
Cylinder bore “C” 89.500
X
89.505 mm
Taper limit “T” 0.05 mm
Out of round “R” 0.03 mm
“C” = Maximum D
“T” = (Maximum D
1
, or D
2
) – (Maximum D
5
or D
6
)
“R” = (Maximum D
1
, D
3
or D
5
)
– (Minimum D
2
, D
4
or D
6
)
If out of specification, rebore or replace the cylin-
der, and replace the piston and piston rings as
set.
2nd step:
Measure the piston skirt diameter “P” with a mi-
crometer.
a
5.5 mm from the piston bottom edge.
Piston size P
Standard
89.420
X
89.435
mm
Oversize 2 0.50 mm
Oversize 4 1.00 mm
If out of specification, replace the piston and pis-
ton rings as a set.
3rd step:
Calculate the piston-to-cylinder clearance with
following formula:
Piston-to-cylinder clearance =
Cylinder bore “C” –
Piston skirt diameter “P”
Piston-to-cylinder clearance:
0.065
X
0.085 mm
<Limit>: 0.15 mm
If out of specification, rebore or replace the cylin-
der, and replace the piston and piston rings as
set.