Original Piaggio upper compression ring for liquid-cooled 300cc and 310cc HPE four-stroke engines. The piston ring with Piaggio original part number 1A011379 is intended for engines equipped with a piston manufactured by Asso S.p.A.
The compression ring is installed in the uppermost ring groove of the piston. It seals the combustion chamber against the crankcase and helps ensure that the gas pressure generated during combustion is used as effectively as possible to drive the piston. At the same time, it supports heat transfer from the piston to the cylinder wall.
Piaggio uses pistons from different suppliers in its HPE engines. In addition to pistons manufactured by Asso S.p.A., versions produced by Fujian Huawei Juquan Precision Technology are also used.
The piston rings are assigned different original part numbers depending on the piston manufacturer:
This product with part number 1A011379 is intended exclusively for the corresponding Asso piston version. The two ring versions must not be considered interchangeable simply because they are used in engines of the same type or displacement.
Before ordering, it is therefore essential to check which piston manufacturer is actually fitted in the engine. The markings on the existing piston and the corresponding Piaggio spare parts specifications are decisive. The vehicle model and year of manufacture alone are not sufficient for reliable identification.
The upper piston ring is exposed to particularly high thermal and mechanical loads. During combustion, gas pressure acts on the piston and its ring assembly. The compression ring limits the passage of combustion gases between the piston and cylinder wall.
Reliable sealing is important for compression pressure, engine performance and smooth engine operation. A worn or damaged compression ring can contribute to increased blow-by, reduced compression and changes in oil consumption.
The ring is designed as an open, circular metal ring. The opening forms the ring end gap, which must have a specified clearance when installed. This clearance accommodates thermal expansion during engine operation, among other factors.
HPE stands for High Performance Engine. Piaggio uses this designation for an advanced generation of high-performance four-stroke engines featuring electronic fuel injection, four valves and liquid cooling.
The 300 HPE and the subsequently developed 310 HPE share a similar basic technical concept. However, the 310cc version features a longer piston stroke and numerous revised engine components.
Although these engine generations differ in displacement and piston stroke, the upper compression ring with original part number 1A011379 is used in the corresponding Asso piston versions of both HPE engines.
Vehicle compatibility applies exclusively to engines equipped with the corresponding Asso piston version. Vehicles fitted with a piston manufactured by Fujian Huawei Juquan require the piston ring version specified for that manufacturer.
Before installation, the condition of the cylinder bore, piston ring groove and existing piston ring assembly must be checked. Particular attention must be paid to the ring end gap inside the cylinder and the axial clearance of the ring in the piston groove. Both measurements must comply with Piaggio specifications.
The piston ring must not be excessively expanded or twisted during installation. If the ring has an installation marking, the specified installation orientation must be observed. Installation must be carried out in accordance with the workshop manual.
A new compression ring cannot compensate for a damaged or worn cylinder bore or an excessively worn piston ring groove. If significant wear is detected, the piston and cylinder must also be inspected to determine whether they can continue to be used.
Piaggio original part number 1A011379 provides a precisely matched replacement for the upper compression ring of the corresponding Asso pistons used in 300cc and 310cc HPE engines. Correct identification of the installed piston manufacturer is essential when selecting the appropriate replacement part.
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