I thought I'd gotten everything working on my SR500 until today. I'd drained the tank and had the old flaking liner removed and a new one, hopefully impervious to gasohol, put in. That took about two weeks. I poured the gas back in and went for a 20 mile ride and everything was fine. Today I fired it up and got about a block. It missed, sputtered, and died. Gas is getting to the carb fine. Compression is fine. There's a filter in the tank and an inline filter in the gas line (which I replaced just to be safe). It'll run anywhere from 5 seconds to a minute or so, but the result is still some missing and sputtering, a halfhearted backfire or two, and it dies. Could the gas have gone bad in two weeks? Come to think of it, that's two weeks plus however long it was in the tank before I drained it and my aged memory isn't that good. So I guess the question is do the symptoms sound like bad gas? If so, I'll drain and replace. If not, it's back to tearing down the carb again - sigh.