http://cid-407d7ef0965d3991.skydrive.live.com/browse.aspx/Racing%20Modelthe owners manual for the RM465X
Cylinder
Decarbon the exhaust ports and the upper part of the cylinder.
Check the cylinder bore for wear by using a cylinder gauge at 20mm from the top surface.
Standard 86.000 - 86.015mm
Service Limit 86.060
Piston
Decarbon the piston crown and the ring grooves.
Minor scuff on the sliding surfaces can be removed by grinding with sandpaper #400.
Measure the piston diameter at the 27.5mm from the piston skirt end.
Standard 85.935-85.940mm
Service Limit 85.880mm
Piston Ring
Check each ring for free end gap.
Standard 8.5mm
Service Limit 6.8mm
To check the piston ring for wear, fit the ring around the lower part of the cylinder and measure the end gap in this condition of the ring, as showen.
If the reading taken exceeds the limit, replace it by a new one.
Standard 0.30-0.50mm
Service Limit 0.85mm