Piston ring, upper -PIAGGIO, Ø=74.5mm- Vespa GTS HPE 300 (ZAPMA3600, ZAPMD310), Vespa GTS Super HPE 300 (ZAPMA360, ZAPMD3100), Vespa GTV HPE 300 (ZAPMA3602, ZAPMA362, ZAPMD3102), Piaggio MP3 HPE 300 (ZAPTA2100, ZAPTD2100)

TIP: Always install piston rings carefully. Piston rings made of cast material are only elastic to a limited extent and break relatively quickly.
Some pistons have trapezoidally profiled piston rings (so-called keystoner rings), these only fit in one installation position. If the ring does not move freely, please loosen it carefully and reinstall it turned 'upside down'.
Very helpful tools for working on the cylinder and/or piston are:

• Piston ring compressor -BUZZETTI- Ø=45-90mm BU5040
• Piston ring pliers BU5045
• Disassembly tool for piston pins -UNIVERSAL- Ø=13, 15, 16, 19, 22mm 7674333
• Impact pin for piston pin -UNIVERSAL Ø=10mm/14,5mm 7674725