Suzuki RM125 - Piston and Piston Ring Inspection

CYLINDER, PISTON AND EXHAUST VALVE 6-7
• Measure the cylinder bore for wear with a cylinder gauge 20
mm (0.8 in) from the top surface.
NOTE:
The cylinder bore must be measured perpendicular to the crank-
shaft axis direction.
 Cylinder bore
Standard: 54.000 – 54.015 mm (2.1260 – 2.1266 in)
 09900-20508: Cylinder gauge set
PISTON AND PISTON RING INSPECTION
• Remove the piston ring from the piston ring groove.
• Remove carbon deposits from the piston.
• Inspect the piston for wear, scratches and damage.
• Measure the piston outer diameter 19 mm (0.75 in) from the
skirt end.
 Piston outer diameter
Service Limit: 53.880 mm (2.1213 in)
 09900-20203: Micrometer (50 – 75 mm)
• Measure the piston pin bore and piston pin diameter.
 09900-20205: Micrometer (0 – 25 mm)
09900-20605: Dial gauge
• Remove carbon deposits from piston ring and piston ring
groove.
• Fit the piston ring into the ring groove and measure the clear-
ance with a thickness gauge.
 Piston ring to groove clearance
Standard: 0.020 – 0.060 mm (0.0008 – 0.0024 in)
 09900-20803: Thickness gauge
• Fit the piston ring into the cylinder and measure the piston
ring end gap with a thickness gauge.
 Piston ring end gap
Service Limit: 0.80 mm (0.031 in)
 09900-20803: Thickness gauge
Service Limit
Piston pin bore 15.030 mm (0.5917 in)
Piston pin O.D. 14.980 mm (0.5898 in)
20 mm
(0.8 in)
19 mm
(0.75 in)