Patrick McDonough, 59, from Middlesbrough was found seriously injured at Buttertubs Pass near Hawes in the Yorkshire Dales on 4 October.
He died in James Cook Hospital in Middlesbrough the following day.
North Yorkshire Police are looking for number of MG sports car drivers who were seen in the area at the time.
Detectives have contacted local motoring clubs in a bid to trace the car owners, but no-one has so far come forward.
Officers said that they are seeking the drivers as witnesses and said "there is no suspicion at this time, that they were involved".
Police also appealed for the occupants of a yellow car seen taking photographs in the area to get in touch.
Police are appealing for the drivers of MG sports cars to come forward as part of an investigation into the death of a cyclist in North Yorkshire.