Mmmm, another ethanol thread. We are gluttons for punishment... :-> The tanks on my cagiva’s all fit fine from the dealer early on, so wasn’t an Italian QC issue. then over time they expanded and became very problematic. Same with other earlier model ducs from back when we had moved beyond metal but didn’t really see the effects of the ethanol yet. As Phil and others have have indicated, clean em out, whichever way works best for you, then either coat the inside or or just convert to non ethanol gas. All my little gas powered stuff at home now, lawnmowers, weed whackers, dirt bikes, are all on clear gas, and none of them have the tank and carburation issues that plagued them before the ethanol issue was highlighted a number of years ago. Pretty dramatic difference on a large number of motors in my little sphere.