Suzuki RM85, Owner'S Service Manual

Page: 75 / 206

6-6 CYLINDER, PISTON AND EXHAUST VALVE
• Inspect for cylinder distortion.

Cylinder distortion
Service Limit: 0.05 mm (0.002 in)
• Measure the cylinder bore for wear with a cylinder gauge 15
mm (0.59 in) from the top surface.
NOTE:
The cylinder bore must be measured perpendicular to the crank-
shaft axis direction.

Cylinder bore
Standard: 48.000 – 48.015 mm (1.8898 – 1.8904 in)

09900-20508: Cylinder gauge set (40 – 80 mm)
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 16 mm (0.63 in) from the
skirt end.

Piston outer diameter
Service Limit: 47.880 mm (1.8850 in)

09900-20202: Micrometer (25 – 50 mm)
• Measure the piston pin bore and piston pin diameter.

09900-20605: Dial gauge
09900-20205: Micrometer (0 – 25 mm)
• 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
15 mm
(0.59 in)

Service Limit
Piston pin bore 14.030 mm (0.5524 in)
Piston pin O.D. 13.980 mm (0.5504 in)
16 mm
(0.63 in)