Piston; End Gap; Piston Pin Check - SHERCO ST Series Workshop Manual

ENGINE ELEMENT CONTROL
❱❘ Piston
• When reassembling a worn piston, check the following points:
• Look for any traces (tightening). Light traces can be removed.
• Ring emplacement: The rings must not get stuck in their emplacement. To clean it, you can use an
old segment or sand paper (400)
• The segment retainers must be securely fastened and must not be worn.
• Rings: Check the condition and end gap.
❱❘ End gap control
• Thread the segment into the cylinder and place it with the piston (approximately 10 mm from the
upper edge of the cylinder).
With a shim we measure the clearance.
•

End gap:

Standard 0.35-0.45mm ,
Limit 0.65mm.
If the clearance is greater than indicated, the condition of the cylinder and the
piston must be checked. If these remain within the tolerance limits, replace only
❱❘ Piston pin control
Piston pin diameter for 125cc:
Standard : 14,998 mm
Limit: 14,995 mm
Piston pin hole diameter for 125cc :
Standard : 15,003mm
Limit : 15,007mm
28
WARNING
the rings.
Piston pin diameter for 250/300cc :
Standard : 17,998 mm
Limit : 17,995mm
Piston pin hole diameter for 250/300cc :
Standard : 18.002 mm
Limit : 18.006 mm
ST SERIES