Polini 70cc Evolution cylinder kit for Yamaha BWS & Slider/ Minarelli Vertical engines.

Polini’s new 70cc Evolution kit is a complete redesign for vertical Minarelli engines, packed with exclusive features to deliver serious performance gains. Using advanced fluid-dynamic engineering, it achieves more power, stronger torque and sharper throttle response than any traditional 70cc cast-iron kit.

Performance is up to 14hp with a broad torque curve on a basic setup. For maximum power: pair with a Polini CP 19–24mm carburettor, Yasuni R exhaust and a Polini high-speed transmission.

Features:
-Integrated reed valve housing with two dedicated ducts feeding directly into the transfers for improved torque and low-rpm response.
-4-petal reed valve (supplied) for faster, more efficient airflow compared to standard 2-petal systems.
-Dedicated flow guide to smooth intake charge and reduce turbulence.
-360° rotatable intake manifold (for Polini CP 17–24mm carbs), compatible with OEM and open filters.
-Racing head with copper gasket, twin-ring piston and base gaskets (0.2 / 0.3mm) for squish adjustment.

Gudgeon Pin: 10mm

Polini 166.0074/E