Honda BF20 BF2A Outboard Motors Manual, Page 43Get this manual
PISTON RING END GAP
TOP SECOND OIL
STANDARD
SERVICE LIMIT
0.1 5-0.35 rnrn (0.0059-0.014 in) 0.2-0.8 rnrn 10.0079-0.031 in)
1 .OO mm (0.039 in)
1.00 mm (0.039 in)
PISTON RING
Before measuring ring end gap, use the piston top to position the ring so it will not be cocked in the cylinder bore
PISTON PIN OD
STANDARD SERVICE LIMIT
10.0 rnm (0.3937 in)
9.950 mm (0.3917 in)