F+,
Put the "thing" on an electric hot plate & put the cranckshaft in the freezer for at least one hour.
Find some welding gloves or equal, take the cranckshaft out of the freezer and put in a vice, mount the "thing" on the the main bearing inner race, sqeeze the blood out of your fingers and at the same time turn & pull upwards.
When the ice on the bearing inner race melts away it will be possible to pull the ring of the crackshaft.