J)Iston Pin And Bearing; Piston - Yamaha YT175J 1982 Service Manual

Max. allowable taper (d - a):
0.05 mm (0.0020 in)
Max. allowable out-of-round
(B - A or A - B):
0.01 mm (0.0004 in)
Wear limit: 56.10 mm (2.21 in)
(at "a" position)
Piston pin and bearing
Apply a light film of oil to pin and bearing sur-
faces. Install in connecting rod small end.
Check for play. There should be no
noticeable vertical play. If play exists, check
connecting rod small end for wear. (Replace
pin and bearing or all as required.)
3-8
Piston
1 . Remove carbon deposit from ring
grooves using old piston ring as shown.
2. Using an outside micrometer, measure
piston diameter. The piston is
camground and tapered. The only
measuring point is at right angles to the
piston pin holes about 10 mm (0.39 in)
from bottom of piston. Compare piston
diameter to cylinder bore measure-
ments.
Piston maximum diameter (as shown
below) subtracted from minimum
cylinder diameter (d - B) gives piston
clearance. If beyond tolerance, hone
cylinder to tolerance or re-bore to next
over-size and fit over-size piston.
10.mm
(O.3Sinl
Piston clearance
0.040 - 0.045 mm
(0.0016 - 0.0018 in)