Cylinder; Piston Pin And Bearing - Yamaha LB50IIAC Service Manual

Cylinder
1. Hone cylinder bore using a hone with
fine stones. Hone no more than re-
quired to remove all wear marks.
2. Using a cylinder gauge set to standard
bore size, measure the cylinder.
Measure front-to-rear and side-to-side
at top, center and bottom just above
exhaust port. Compare minimum and
maximum measurements. If over to-
lerance and not correctable by honing,
rebore to next over-size.
Max. allowable taper:
0.05 mm
Max. allowable out-of-round:
0.01 mm
Piston pin and bearing
1. Check the pin for signs of wear. If any
wear is evident, replace pin and bearing.
2. Check the pin and bearing for signs of
heat discoloration. If excessive (heavily
blued). replace both.
N O T E : - - - - - - - - - - - -
Shiny spots on pin from race wear are
normal. Replace pin and bearing only if
wear is excessive (indentation on pin,
etc.)
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