What causes the oil light to stay on in a 2005 roadking?

Answer 1

Low oil level or low oil pressure. Low oil pressure could be caused by dirty oil, clogged oil filter or a bad oil pump

Answer:Bike or Car...

Dirty oil will not cause a light to come on, and "clogged" filters are Bypassed via Bypass Valves.

Oil filter "Clogging" is only possible by media failure in a filter which has been on an engine for several thousand miles past its service life of 3,000 miles and should any failure occur, it would be contained and bypassed.

Oil filters are after the pump in the flow

NO OIL PRESSURE = No Oil or Bad Pump... This is what triggers Idiot lights.

A bad oil pressure switch could also cause the light to stay on but is not likely the cause on a bike or vehicle of that age.

Oil Pressure Switches trigger lights, while Oil Pressure Sending Units are for oil pressure gauges.

If the most common causes above are not your case, then the last possible cause would be a grounded Oil Pressure Switch wire pinched or rubbed through somewhere.