Polini 78.8cc Big Bore Kit for Vespa Piaggio 4T 50cc Engines

Polini 78.8cc Big Bore Kit for Vespa Piaggio 4T 50cc Engines

This upgrade kit enlarges a 49cc Piaggio 4-stroke engine to 78.8cc, aiming to add power and speed. Its main parts are a finned aluminum cylinder and a flat-top piston, so it suits anyone looking to improve their scooter's performance. It is one of the Vespa scooter parts meant to raise both mid-range and top-end output. Intended for closed-course competition and off-road riding, this kit is not meant for use on public roads.

Build and Parts Included

The cylinder is made from finned aluminum alloy, which helps it shed heat. The package also contains a flat-top piston, a set of piston rings, and every gasket and fastener needed for fitting. The compression ratio is 11.6:1, designed with maximum power output in mind.

Power and Gearing Benefits

Beyond the larger displacement, this kit comes with a 14:43 gear-up ratio, which is a 60% change from the stock 11:54. That gearing change is meant to support higher top speed, so it fits racing and other competitive riding.

Specifications

• Displacement: 78.8cc
• Compression Ratio: 11.6:1
• Gear-Up Ratio: 14:43
• Cylinder Material: Aluminum alloy
• OEM Part Number: 140.0223
• Made in: Italy
• Fits: Vespa and Piaggio 4-stroke 49cc engines (2-valve and 4-valve) with 78.8cc big bore upgrade

Compatible Models

Works with:

• Vespa LX 50 (2006-2009, 4-stroke 2-valve)
• Vespa LX 50 (2010-2014, 4-stroke 4-valve)
• Vespa S 50 (2009-2014, 4-stroke 4-valve)
• Vespa Primavera 50 4V Carb (2015-2019)
• Vespa Sprint 50 4V Carb (2015-2019)
• Piaggio Fly 50 (4T)
• Scootcoupe P50

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