Use the micrometer to measure at several points around the ring.
Piston Ring Thickness Standard:
Top [A] 0.77
0.79 mm (0.0303
0.0311 in.)
Second [B] 0.78
0.79 mm
(0.0307
0.0311 in.)
Service Limit:
Top 0.70 mm (0.0276 in.)
Second 0.71 mm (0.0280 in.)

If any of the measurements is less than the service limit on either of the rings, replace all the rings.
NOTE
When using new rings in a used piston, check for uneven groove wear. The rings should fit perfectly parallel to the groove sides. If not, replace the piston.
Piston Ring Groove Width Inspection
Piston Ring End Gap InspectionOperating Procedures
Clean the seat area carefully.
Coat the seat with machinist’s dye.
Fit a 45° cutter into the holder and slide it into the valve
guide.
Press down lightly on the handle and turn it right or left.
Grind the seating surface only until it is smooth.
NOTICE
Do not grind the seat too ...
Ignition Switch Replacement
Remove:
Air Cleaner Housing (see Air Cleaner Housing Removal
in the Fuel System (DFI) chapter)
Disconnect the lead connectors [A].
Remove:
Steering Stem Head (see Stem, Stem Bearing Removal
in the Steering chapter)
Using a small chisel or punch [A], turn out the Torx bolts.
...
Valve Installation
NOTICE
Do not lap the valve to the valve seat, using the
grinding compound. It will come off oxide film
treated surface of the valve.
Replace the oil seal with a new one.
Apply a thin coat of molybdenum disulfide grease to the
valve stem before valve installation.
Install the springs so ...