Polini Evolution iron cylinder kit 70cc Minarelli Vertical b.10mm

Polini cylinder Evolution iron 70cc kit, 10mm pin for Minarelli Vertical.

The Polini Evolution iron 70cc cylinder kit for Minarelli vertical engines (MBK Booster, Yamaha, etc.) is designed for those seeking a true leap in performance. This version with a 10 mm pin is based on a very solid technical foundation, optimized for competition or demanding sport use.

Although it is a cast iron cylinder, nothing in this kit is conventional. Polini has completely redesigned the thermal group, applying solutions that are usually only seen in high-end engines. The result: more power, more torque, and better response throughout the entire rev range.

Among the key innovations is the integrated reed box in the cylinder with two exclusive channels that feed the transfers directly, improving engine charge and low RPM thrust. In addition, the kit includes a 4-petal reed box, much more effective than the traditional 2-petal ones, and a 360° manifold compatible with Polini CP carburettors from 17 to 24 mm. This allows you to fit the filter you prefer without issues of space or orientation.

With the recommended configuration, this kit can deliver up to 14 real HP, a figure well above what is usual in iron kits. The torque curve is constant and full, perfect both for acceleration and for maintaining speed on straights.

Technical features:

• Stroke: 39.2 mm
• Connecting rod: 80 mm
• Cylinder diameter: 47 mm
• Recommended squish: 1 ± 0.1 mm
• Ignition advance: Original
• Recommended Spark plug: NGK heat grade 9
• Suggested carburettor setup:
• Polini CP 24 carburettor
• Open cone-type air filter
• Main jet: 113
• Pilot jet: 38
• Slide: Ø25/30
• Needle: 14/22 in 2nd groove
• Atomizer: 2.7
• Float: 5 g

Recommended parts

• Polini CP carburettor from 19 to 24 mm (ideally the 24 with open cone-type filter)
• Polini For Race 4 or Scooter Team exhaust
• High-Speed transmission or sports variator