Clutch spring Piaggio scooter 50cc Evo Slider Polini

The stiffness of the contrast spring plays an important role in the transmission of power from the engine to the rear wheel.
It exerts back pressure on the rear pulleys and therefore has a considerable influence on the operation of the variator. The contrast spring is usually stiffer if the belt tends to slip, if the variator does not work at the optimum RPM level or if the engine is still running below the optimum RPM despite light weights.
What has a negative influence on engine performance is a twisted contrast spring. With the Evo-Slider plate the manufacturer Polini has solved this problem.

It is a small plate that is mounted between the contrast spring and the clutch, which reduces the torsion to a minimum. In addition, the Polini Evo-Slider absorbs vibrations of the pulleys at high RPM.

The result is a slimmer engine and a better power transmission to the rear wheel.
The thicker the diameter, the harder the contrast spring.
Choose the size according to the % increase in hardness or -% softer than the original
The kit includes a harder or softer spring and an Evo-Slider supplement.
The Polini Evo-Slider allows the spring to rotate, which significantly improves the Maxiscooter's handling at standstill and the throttle response