Don, that 185 coil may be for a CDI? It may be marked CD or CDI on the plastic covering the coil winding. If so, the primary coil resistance (measured between the grounded armature and the single wire) will be very low, and will fry the points in a very, very short time.
Are you sure the original coil was damaged? With 12V applied to a 6V coil, the current increase would also be hard on the points. The simple solution, besides not leaving the key on, would have been to install a ballast resistor inline with the coil input.