The rings should fit perfectly parallel to groove surfaces.
If not, replace the piston and all the piston rings.
Piston Ring/Groove Clearance Standard:
Top 0.03 
0.07 mm (0.0012
0.0028 in.)
Second 0.03 
0.06 mm (0.0012
0.0024 in.)
Service Limit:
Top 0.17 mm (0.0067 in.)
Second 0.16 mm (0.0063 in.)
Piston Wear Inspection
Piston Ring Groove Width InspectionExternal Shift Mechanism Removal
Remove:
Shift Lever (see Shift Pedal Removal)
Oil Pump Drive Gear (see Oil Pump Drive Gear Removal/
Installation in the Engine Lubrication System
chapter)
Circlip [A]
Washer [B]
Special Tool - Outside Circlip Pliers: 57001-144
Remove:
Shift Shaft Assembly [A]
Washer [B] ...
Sidestand Installation
Replace the sidestand nut [A] with a new one.
Apply grease to the sliding areas [B].
Tighten the sidestand bolt [C] first, and then the sidestand
nut.
Torque - Sidestand Bolt: 44 N·m (4.5 kgf·m, 32 ft·lb)
Sidestand Nut: 29 N·m (3.0 kgf·m, 21 ft·lb)
Install the spring [D] as sh ...
Piston Wear Inspection
Measure the outside diameter [A] of each piston 5 mm
(0.20 in.) [B] up from the bottom of the piston at a right
angle to the direction of the piston pin.
If the measurement is under service limit, replace the piston.
Piston Diameter
Standard: 75.959 75.974 mm
(2.9905 2.9911 in.)
...