A 73-year-old man suffered injuries to his face in the assault, which happened on Thursday, April 4 at 3.15am.
The pair are reported to have been driving a scooter along Broadway in Dunscroft when they stopped and threw an unknown object at the man while he was walking his dog.
It is believed that the men on the motorcycle were not wearing helmets and are known to frequent the area.
Anyone who recognises the men should call South Yorkshire Police on 101 quoting reference number 14/56058/19.
