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 InspectionRear Caliper Removal
Remove:
Bolt [A]
Rear Wheel Rotation Sensor [B]
Loosen the banjo bolt [C] at the brake hose lower end,
and tighten it loosely.
Loosen the caliper holder pin [D].
Remove the rear wheel (see Rear Wheel Removal in the
Wheels/Tires chapter).
Unscrew the banjo bolt and remove t ...
Battery Ground
Before completing any service on the motorcycle, disconnect
the battery cables from the battery to prevent the engine
from accidentally turning over. Disconnect the ground
cable (–) first and then the positive (+). When completed
with the service, first connect the positive (+) cable to the
p ...
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 ...