this has been going round for ages and is a big concern with the VMCC and vintage car owners. why are fuel tanks rusting quicker, bare metal in a tank and ethanol being hygrascopic absorbs water , rusts tanks and messes up carbs. also if you have treated the inside of a classic tank it peels off the early tank sealers, ironic really as normally you wouldnt be able to get it off once applied.
seeing more and more bikes in for carb cleans after winter layups and non starting yet recently Ive bought a couple of 5+ year non used bikes and within a couple of mins with the boost pack they fire up.