how can i fix the exhaust on my speedfight 100?

there is smoke coming out of the righthand side of my scooter it seems to be coming from under nieth the fairing where the exhaust is and it is makeing a load noise from the exhaust i toke the seat and the iner well of and have noticed the the exhaust is only held on with one bolt and the seems to be a gap at the exhaust and the engine i think there is supost to be a gasket or somthing there to stop the any air or fumes escaping could any body help with some info on how to fix this thanks