These are new old stock original Gilera 6-1/2" pieces of U-channel rubber moulding or edging that serves as the chainguard gasket for Gilera 98, 124 4V, 124 5V, & 150 5V models and Sears 106SS & 124 5V motorcycles. It's item number 26 in the last photo. This U-channel molding is also useful for many English and other European vintage motorcycles to go between number plates and fenders, toolboxes and lids, and other places where 2 pieces of metal meet. 

My name is Tony Schanz, I formerly ran DomiRacer Distributors in Cincinnati, Ohio buying and selling vintage English, Italian, & German motorcycle parts, tools, accessories & memorabilia. DomiRacer closed 6/11/2013, but I still deal in parts, motorbikes, decals, advertising, photos, posters, & more. Please add my store, The Real DomiRacer, to your favorite sellers and watch for other rarities in my future eBay listings.