
Polini Big Evolution variator casing for horizontal Minarelli shafts – Manufacturer reference: 170.0306
Designed for urban scooters and competition, this POLINI Big Evolution variator casing features a specific machining aimed at reinforcing the primary shaft support. An additional bearing can be inserted into the casing via a bolted extension on the shaft, which limits bending under load and stabilizes the variator drive pulley.
The casing also integrates air intakes distributed across its surface to improve cooling of the variator/belt assembly and reduce thermal deformation. Expected results include a more linear transmission behavior, less annoying vibrations, and a more complete utilization of the belt's travel range, useful in intensive use or road/competition preparation.
Indicative compatibilities: Aprilia SR 50 R (2022), Yamaha AEROX R (SA421) (2018), Rieju RS 50 Sport (2018). Please check the fitment on your model before installation.