Repair and upgrade kit for the primary gear reduction of all Vespa Wideframe engines, e.g. Vespa VM, VN, VL, VB, VNA, VNB, VBA. The springs contained in the large primary gear serve as shock absorbers. They protect the gear unit from high load peaks. If they are too soft in relation to the engine torque, they are completely compressed and give the unfiltered peak pressures to the gearbox.