Cylinder Polini Aprilia Sportcity One / Vespa 50cc 4T 4V

Polini kit for Vespa 50 4-stroke 4 valve scooter.

The Bergamo-based company has created a thermal unit consisting of cylinder and piston that improves acceleration and top speed.

It has a number of technical features:

• Cylinder with diameter increased to 49 mm cast in light aluminium alloy to guarantee greater thermal stability.
• Nickel-silicon alloy tube; particularly resistant to wear and abrasion; improves piston sliding.
• Gravity cast piston in light alloy with high silicon content with "omega" design. It allows to contain the thermal expansion and to reduce the clearance. The piston design is specific to optimise the compression ratio. The piston is composed of two piston rings, the upper one is chrome-plated, the other one is composite.
• The cylinder head gasket is made of stainless steel with fluorinated technopolymer coating to reduce temperatures and increase gas retention at high temperatures.