Cylinder Polini P.R.E 4 70cc 47.6mm Minarelli / Piaggio scooter 50 LC

Cylinder Polini P.R.E 4 70cc 47.6mm for Minarelli / Piaggio 50 LC scooter.

If you are preparing your bike for the track, with Polini PRE 4 or Malossi RC or C-One crankcases, you can't miss the Cylinder Polini P.R.E 4 70cc FL system.

The Polini engineers have optimized the Cylinder with a compression ratio of 16.5:1, a Squish 0.45mm and much larger transfer ports allowing for a much greater filling compared to the previous PRE 3 model.

This translates into a much higher performance than its predecessors, you will notice it from a standstill, much more response and acceleration while also increasing torque.

Cooling has also been improved, operating at around 50-55º, definitely a point to consider on the track, the fuel must be at least 100 octane and a mixture of 3.5-4%.

It is undoubtedly a component made from pure engineering, but keep in mind that if you want to squeeze the most out of the Cylinder you must install other components.

Advice

• Polini Oversize transmission kit
• Polini PRE 4 exhaust
• Carburettor Voca PWK 24 to 30
• reed valve Vforce 4
• Crankshaft Polini P.R.E 4

Technical specifications

• Diameter (mm): 47.6
• Stroke (mm): 39.3
• Displacement (cm"): 69.9
• Piston pin (mm): 13
• Squish (mm): 0.45
• Length of Connecting rod (mm): 90
• Ring gap (mm): 0.25-0.30
• Piston - 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
• Mixture percentage: 3.50-4%
• Optimal operating temperature (ºC): 50-55
• Gasoline: 100 octane