Mikuni Top Cover For Mikuni Hsr42 / Hsr45 When thinking of anything carb related one name that comes to mind for many is Mikuni . They offer replacement carb tops to meet and succeed your needs. This carb top is intended to be used in conjunction with Hsr42/45 carbs. Features: Brightens up the top of your Mikuni HSR series carbs with chrome Chrome top cover has the Mikuni 'M' and HSR logo on the top Cover includes mounting hardware and a fresh gasket