Inspecting The Small End; Inspecting The Wrist Pin; Inspecting The Piston - Derbi GP1 125-250 c.c. Workshop Manual

I I
NSPECTING THE SMALL END NSPECTING THE SMALL END
- Using a micrometer, measure the connecting rod small end
diameter.
N.B.
IF THE CONNECTING ROD SMALL END DIAMETER EXCEEDS
THE STANDARD DIAMETER, EXHIBITS WEAR OR OVERHEA-
TING, PROCEED TO REPLACE THE DRIVING SHAFT.
Characteristic
Checking the connecting rod small end: Maximum diameter
15.030mm
Checking the connecting rod small end: Standard diameter
15.015-15.025mm
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NSPECTING THE WRIST PIN NSPECTING THE WRIST PIN
- Check the pin outside diameter.
- Calculate the coupling clearance between pin and connec-
ting rod end.
Characteristic
Piston pin diameter : Standard clearance
0,015÷0,029 mm
Piston pin diameter : Standard diameter
14,996÷15,000 mm
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NSPECTING THE PISTON NSPECTING THE PISTON
Version 125
- Measure the diameter of the wrist pin housing on piston.
- Estimate the clearance between wrist pin and piston.
- Measure the external diameter of the piston, perpendicular
to the wrist pin diameter.
- Take this measurement at 41.1 mm from the piston crown,
in the position shown in the figure.
- Clean the piston ring grooves thoroughly.
107