The pensioner was held by police over six incidents in Leeds city centre on February 23 and another in Dewsbury on February 21.
He is now on police bail pending further enquiries.
The Dewsbury incident involved a 15-year-old girl who reported seeing a man committing a lewd act on the top deck of a number 202 Dewsbury to Leeds bus in Bywell Road, Dewsbury, around 11.30am on Sunday, February 21.
Sergeant Pat Kenning, of Leeds City Neighbourhood Policing Team, said: “There were a number of other people on the bus at the time and we would like trace them as potential witnesses to this incident.”
Anyone with information is asked to contact Sgt Kenning at Leeds Central Police Station on on 0113 241 3833 or via 101 quoting crime number 13160079331.