Cylinder kit Polini Evolution P.R.E 4 70cc (Piaggio)

The Polini Evolution P.R.E. 4 – 70cc Cylinder Kit is an extreme racing cylinder kit designed for Piaggio 2-stroke engines.

This cylinder is designed for:

- High RPM
- Maximum power
- Track/drag/running use

P.R.E. 4 technology is based on an ultra-aggressive transfer port design, a very high port timing, and tight tolerances, resulting in a complete and consistent engine configuration.

Specifications:

Bore (mm): 47.6
Stroke (mm): 39.3
Displacement (cc): 69.9
Piston pin (mm): 13

Squish (mm): 0.45
Connecting rod length (mm): 90
Ring ring tolerance (mm): 0.2-0.25
Piston-to-cylinder clearance (mm): 0.05-0.06
Compression ratio: 16.5
Tightening torque - cylinder M7 (Nm): 14
Tightening torque - cylinder head M7 (Nm): 14
Tightening torque - cylinder head M5 (Nm): 8
Kart track fuel mixture percentage: 3.50%
Race track fuel mixture percentage: 4%
Optimal operating temperature (°C): 50-55