Cowl Rubber (Thin, Gray); Allstate, Vespa 250 Air Box Cover

Air Box Cover

this belt is constructed with specialized EPDM rubber compounds and high-tensile cords to resist the heat and stretching that lead to "belt snap" in tuned GY6 engines

While wiring is straightforward

but you would have to drill out the hole on the frame bigger (11mm to 13mm)

Cowl Rubber (Thin, Gray); Allstate, Vespa 250 Air Box CoverThinner Grey cowl rubber for all 1950s and early 1960s Largeframe model Vespa and Sears Allstate scooters. Also available in Black Sku: 23088 B . Fits Models: VNA Vespa 125 57 59 125 Large Frame 8 in. VNB Vespa 125 59 66 125 Large Frame 8 in. VBA Vespa 150 58 60 150 Large Frame 8 in. VBB Vespa 150 60 67 150 Large Frame 8 in. VS5 Vespa GS 150 58 61 150 Large Frame 10 in.