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 InspectionFront, Rear Wheel Rotation Difference Abnormal Inspection (Service Code b
25)
Check the following and correct the faulty part.
Incorrect Tire Pressure
Tires not recommended for the motorcycle were installed
(incorrect tire size).
Deformation of Wheel or Tire
Missing Teeth or Clogging with Foreign Matter of Sensor
Rotor (see Wheel Rotation Sensor Rotor Inspe ...
Wheel Alignment Inspection
Check that the notch [A] on the alignment indicator [B]
aligns with the same swingarm mark or position [C] that
the other side alignment indicator notch aligns with.
If they do not, adjust the chain slack and align the wheel
alignment (see Drive Chain Slack Adjustment).
NOTE
Wheel align ...
Main Throttle Sensor Input Voltage Inspection
NOTE
Be sure the battery is fully charged.
Turn the ignition switch to OFF.
Remove the throttle body assy (see Throttle Body Assy
Removal in the Fuel System (DFI) chapter).
Do not disconnect the connectors of the throttle body
assy.
Disconnect the main throttle sensor connector ...