アリババババやイベーイで、支那だか台湾だか、原付用簡易屋根売ってるけどな
https://www.ebay.com/itm/Motorbike-Canopy-Motorcycle-Roof-Motor-Sun-Visor-Shade-Tent-Umbrella-Windshield-/142524057603
https://www.alibaba.com/product-detail/Plastic-transparent-motorcycle-roof-canpony-for_60564685155.html