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 InspectionTorque Limiter Installation
Apply molybdenum disulfide grease to the torque limiter
shaft [A].
Install the torque limiter [B], the collar [C] and the shaft.
Turn the large-hole end of the shaft to inside as shown in
the figure.
Replace the washer [D] with a new one.
Apply a non-permanent locking agent to the t ...
Check 3-5: Warning Indicator Light (Red LED) (Oil Pressure Warning)
Inspection
Connect the leads in the same circuit as Check 3-2.
Connect the terminal [10] to the battery (–) terminal.
Check that the oil pressure warning symbol [A] and the
warning indicator light (Red LED) [B] go on.
If the indicator light does not go on, replace the meter unit.
...
Separator Operation Test
WARNINGGasoline is extremely flammable and can be
explosive
under certain conditions. Turn the ignition
switch OFF. Do not smoke. Make sure the area is
well-ventilated and free from any source of flame
or sparks; this includes any appliance with a pilot
light.
...