140.0208 Polini Big Evolution - D 52 P.13 Aluminium Cylinder / Power Kit Gilera 50 DNA / Sunner / SP / Poggia

Polini Big Evolution Cylinder Kit:  Aluminium Cylinder / Piston Pin D.13 / 52mm Bore / 93.44cc / 15:1 Compression

“BIG EVOLUTION” KIT - The new Polini BIG EVOLUTION cylinder kits for scooters equipped with Minarelli and Piaggio engines are available is three different sizes:
- One with bore: 47,6mm - stroke:39,3mm - displacement: 70cc
- One with bore: 52mm - stroke:39,3mm - displacement: 84cc
- One with bore: 52mm - stroke:44mm - displacement: 94cc
The aluminium cylinder, with closed-deck cooling system, features a specific working, which increases the thermal stability of the cylinder, cutting the risk of barrel distortion even at the highest temperature. The cylinder liner has a nickel -chrome coating. The head plane is brand new and innovative compared to the ones already present on the market: it features a nickel coating to avoid the detonation problems and then worked on with known process in advanced productive CNC centres that grind it with a centesimal calibration.

In this way the head plane is perfectly coupled to the cylinder improving the combustion phase in the burning chamber and increasing the head and cylinder’s life It has 5 transfer ports plus an exhaust port with central bridge to optimise the gas scavenging

The distribution diagram is brand new for its performance features. The piston is gravity die-cast in light alloy at high silicon content with a chromed, grinded, and lapped cast iron ring.

The head is gravity die-cast from a block and later thermal treated to harden the material the same as for the cylinder: the mechanical resistance can be compared to a head machined from a block.

CASE BORING AND CRANKSHAFT REPLACEMENT
Before assembling the cylinder it’s necessary to bore the cases both in the crankshaft and in the cylinder housing.

It is necessary to replace the original crankshaft with the new Polini 85mm one
complete with coil.

Compatible

• APRILIA : SR 50 R-FACTORY (Motore Piaggio)
• DERBI : GP1 50 2001-2003
• GILERA : DNA 50 - RUNNER 50 - SP - POGGIALI
• PIAGGIO : EXTREM LC - MC2-98 - NRG MC3 H2O - NRG-NTT-MC2 - QUARTZ - ZIP 50 SP H2O - ZIP 50 SP H2O mod.2000

ATTENTION: THIS CYLINDER KIT MUST BE FITTED WITH THE CRANKSHAFT cod.210.0021