Use a vernier caliper at several points around the piston.
Piston Ring Groove Width Standard:
Top [A] 0.82 
0.84 mm (0.0323
0.0331 in.)
Second [B] 0.82 
0.84 mm
(0.0323 
0.0331 in.)
Service Limit:
0.92 mm (0.036 in.)
Second 0.92 mm (0.036 in.)
If the width of any of the two grooves is wider than the service limit at any point, replace the piston.
Piston Ring, Piston Ring Groove Wear Inspection
Piston Ring Thickness InspectionEngine Oil Flow Chart
1. Oil Screen
2. Oil Pump
3. Oil Pressure Relief Valve
4. Oil Filter
5. Oil Pipe
6. Oil Cooler
7. Balancer Oil Passage
8. Main Oil Passage
9. Crankshaft Oil Passage
10. Oil Pressure Switch
11. Camshaft Oil Passages
12. Drive Shaft Oil Passage
13. Output Shaft Oil Passage
14. Starter ...
Gear Position Switch Removal
Remove:
Oil Pump (see Oil pump Removal in the Engine Lubrication
System chapter)
Engine Sprocket (see Engine Sprocket Removal in the
Final Drive chapter)
Fuel Tank (see Fuel Tank Removal in the Fuel System
(DFI) chapter)
Disconnect the connector [A].
Remove:
Screws [A]
...
Camshaft, Camshaft Cap Wear Inspection
Remove the camshaft caps (see Camshaft Removal).
Cut the strips of plastigage (press gauge) to journal width.
Place a strip on each journal parallel to the camshaft installed
in the correct position.
Tighten the camshaft cap bolts and upper camshaft chain
guide bolts to the specified ...