um UXPW125, Service Manual

Page: 46 / 110

UXPW
125 ENGINE SERVICE MANUAL AND EFI DIAGNOSTIC
- 46 -
5.4.2. Check cylinder block
5.4.2.1. Check diameter of cylinder bore. When doing
this task, measure the diameter at three layers
respectively, i.e. top, middle and bottom of piston stroke,
and measurement shall be taken at two directions
mutually perpendicular at every layer.
Limit value Φ52.5mm
5.4.2.2. Calculate cylindricity of cylinder bore in
accordance with the maximum value measured at the
positions.
Limit value 0.10mm
If the measurement exceeds the service limit, the
cylinder block must be replaced with a new one.
5.4.2.3. Test of cylinder body flatness
Limit value 0.10mm
5.4.2.4. Check guide plate of chain for evident wear or
damage. If there is, replace the plate with a new one.