Hi, Im Bill, An old time biker. I have experienced, and solved this problem. It almost drove me crazy before it did. I believe this to be a problem with all V Star 1100 models, not just yours. The problem is that small amount oil seepage droplets is comming through the vacuum hose from the crankcase, gathering in the big oil chamber housing that sits on top of your carbs and is sucked into your carbs. It is only a small amount, but enough to foul your plugs. Cleaning or replacing your plugs is only a temperary help, They will immediately foul again until you fix the problem. The way I origionaly fix the problem was that I took a small can, soldered a small copper inlet tube in order to reconnect the vacuum line and rigged an oil trap. Then I fastened it to the inside of the air chamber that sits on top of the carbs. The oil would be caught in the can, preventing the oil from leaking into the air chamber and then down the carbs. But before you do this there may be a simpler way(if it works). There may be to much oil in your crank case. Simply, reduce the amount of oil in your crank case. There is a red light that will turn on if the oil is to low for the oil pump to work. If the red light is off you are safe from being to low on oil. You may go so far to suck some of the oil out of your crank case in small amounts until the oil light comes on, then add a few ounces at the time until the light goes out, and then add a tea cup or so. just to be sure you have reasonable reserve. Ride the bike and see that the light stays off. This may be all you need if this doesn´t work go back to plan \