Polini x4 Clutch Spring set for Aprilia / Piaggio 50cc 2T / Aprilia Ditech / TGB 50cc / SYM Jolie.
Clutch springs which are stiffer than the average stock springs; meaning the clutch engages later allowing the engine to create higher revs at the point of engagement. The Polini kit comes with 4 sets, of varying stiffness, to give greater tuning control to suit the individual scooter.
Scooter clutches consist of 3 pivoting shoes, attached to a backing plate. Between each shoe are small springs that pull the shoes together. The clutch is spun by the torque driver (rear pulley of the transmission), as the RPM increases the centrifugal force on the shoes increases, forcing the shoes out as the springs stretch. the clutch is housed in a clutch bell, as the clutch expands it grabs onto the inner surface of the clutch bell, grips and engages causing the power from the motor to be transferred to the wheel via the clutch bell.
Performance clutch springs are stiffer, and require more centrifugal force to stretch and allow the clutch to engage, therefore more RPM is required. This allows the engine to rev to a higher RPM before load is placed in it. Performance parts such as exhausts, and cylinder kits require more RPM to make power.
Installing stiffer clutch springs allows the engine to reach the higher RPM required before the clutch engages, so that at the point of engagement the engine is producing good power for maximum take off speed.
To put it simply, stiffer clutch springs allow the engine to rev harder before the clutch engages – giving you the maximum off the mark punch.
|Clutch springs scooters|
|wire size 1:||1.7 mm|
|wire size 2:||1.8 mm|
|wire size 3:||1.9 mm|
|wire size 4:||2 mm|
|number of coil:||8|
|number of coil 2:||6|
|number of coil 3:||6|
|number of coil 4:||6|
|engaging engine speed 1:||4000 [rpm]|
|engaging engine speed 2:||5000 [rpm]|
|engaging engine speed 3:||6000 [rpm]|
|engaging engine speed 4:||7000 [rpm]|