Carl throws the biker's skull at the headless body. It strikes him in the chest and bounces away, but the next shot of the biker's skeleton shows the head connected to the body.
When the skeleton of the rider is seen at the end the bones have clearly been wired together.
Kolchak's narration states that it's February, but no only is no snow or no sign of it being cold, there are no bare trees to show it's the middle of winter.
The headless motorcyclist appears to have stood close to nine feet tall before being decapitated.
At the time of the episode airing Chicago was still the second most populous city in the United States. The property warehouse for the city and county would have been far larger than the small garage that is the setting for most of the episode.
Kolchak's narration describes Lila's sister Coral as "a respectable housewife," but she is shown closing and locking up a restaurant just before the motorcyclist kills her. It would have been more accurate to describe her as "a respectable restaurateur".