Honda FQ650, Manual

Page: 99 / 130

CYLINDER BLOCK
13-8
PISTON PIN O.D.
Measure and record the piston pin O.D. at three points
(both ends and middle). Take the minimum reading to
determine piston pin O.D.
If the measurement is less than the service limit,
replace the piston pin.
Inspect the piston pin bore I.D. (page 13-7).
Inspect the connecting rod small end I.D. (page 13-10).
PISTON PIN-TO-PISTON PIN BORE
CLEARANCE
Subtract the piston pin O.D. from the piston pin bore
I.D. to obtain the piston pin-to-piston pin bore
clearance.
If the calculated clearance is more than the service limit,
replace the piston pin and recheck the clearance.
If the clearance is still more than the service limit with a
new piston pin, replace the piston.
PISTON RING SIDE CLEARANCE
Measure the clearance between each piston ring and
ring groove of the piston using a feeler gauge.
If any of the measurements is more than the service
limit, inspect the piston ring width.
If the piston ring width is normal, replace the piston and
recheck the clearance.
If necessary, replace the piston rings (top, second, oil)
as a set and recheck the clearance.
If any of the measurements is still more than the service
limit with the piston rings, replace the piston.
STANDARD: 17.992 – 17.998 mm (0.7083 – 0.7086 in)
SERVICE LIMIT: 17.954 mm (0.7068 in)
STANDARD: 0.004 – 0.016 mm (0.0002 – 0.0006 in)
SERVICE LIMIT: 0.06 mm (0.002 in)
STANDARD:
Top: 0.035 – 0.070 mm (0.0014 – 0.0028 in)
Second: 0.045 – 0.080 mm (0.0018 – 0.0032 in)
SERVICE LIMIT:
Top: 0.15 mm (0.006 in)
Second: 0.15 mm (0.006 in)