Recently purchased an 2002 Rancher 4x4 ES. It has been jetted and has a K&N air filter with a Supertrapp exhaust. Plug is NGK Iridium. Bike runs fine but plug and the end of the exhaust have black deposits on them. Is this a jet issue or does the carburator need adjustment. Can't get the screws off of the end cap of exhaust to see how many discs there are, they are frozen. Is there an adjustment on the jets or should i look into going a little smaller? Any help would be appreciated.
Thanks