Polini Racing Parts - High-Performance Torque Spring Polini Evo-Slider for Piaggio Engines in Aprilia, Derbi, Italjet, Piaggio, and Vespa Scooters
Counterpressure springs are important for tuning in the variomatic and should be changed when the drive belt starts to slip, the variomatic doesn’t sync with the revs or the engine is under the powerband, despite having lighter weights. The plastic slider plates in the Evo mean the counterpressure springs no longer sit directly on the clutch, meaning a reduction in distortion. The larger the diameter, the harder the spring should be.
Counterpressure springs are important for tuning in the variomatic and should be changed when the drive belt starts to slip, the variomatic doesn’t sync with the revs or the engine is under the powerband, despite having lighter weights. The plastic slider plates in the Evo mean the counterpressure springs no longer sit directly on the clutch, meaning a reduction in distortion. The larger the diameter, the harder the spring should be.
