You should look under the carbs and jetting posts here to find out the definative answer to that question but the short answer is the T is running quite lean at idle and you need to rejet the carbs.Buzzy the biker put the answer in one of his posts and I took his advice. YOU should shim the metering rod (main jet) with a #4 washer and increase the size of the pilot or idle jets to a #45 .This mod plus a K&N air filter and either Jardine slip ons or drill out some of the baffles in your stock pipes will give your T a whole new personality .In a word WOW . Oh yes and the cough will go away.