I bought a 2003 V Star 1100 with about 40k miles. The bike ran very well but back fired, mainly on deceleration. This was anoying me so I took it to a local shop. The bike had after market pipes (unknown make) and I was told that the carbs needed to be jetted. I asked him to do that and requested that he check it over and fix anything else that he thought should be done. He worked on the carbs for me, replaced the exhaust gaskets, and one of the valve covers. (Cost of a little over 600.00) There was no more backfireing and the motercycle seemed to be runing very well for about 400 miles. One day I went to the store and it was running fine when I got back home and parked it, but a couple of days later I started it up and it was running on just one cylinder. I rode it back to the motorcycle shop (about 5 miles) to have them look at it. They listened to it and said they were sure that it was either a bad wire or a coil, and asked me to leave it with them. I checked back about a week later, he showed me where it had oil in the air box and said that the only thing it could be is a bad ring, and told me that I was looking at about 1500.00 to fix it. The motorcycle was running fine, did not smoke, wasn't burning any oil, and did not seem to have a miss. When it was worked on there was obviously no signs of a ring problem. As far as I know they havn't done a compression test or anything, just saw the oil in the air box and made their diagnosis. Could this be something else, or even possible something caused by something they did that may have caused the problem.