It happened at around 4.20pm on Wednesday (2/6) in which a black Suzuki GSXR 750 motorcycle was travelling along the A413 towards Winslow when it was involved in a collision with another car that was travelling in the same direction.
The other car, which is described as a baby blue coloured vehicle, possibly a Honda Civic, did not stop.
The rider of the motorcycle left the road and sustained serious arm injuries. He was taken to hospital for treatment where he remains.
No arrests have been made.
Investigating officer, PC Richard Hinds, of the Joint Operations Roads Policing Unit, said: “I am appealing for anyone who may have witnessed this incident to please come forward.
“I would also ask any motorists with dash-cams and who were in the local area at around the time of this collision to please check the footage in case it has captured something that may assist with this investigation.
“Anyone with information can contact police by making a report online, or calling 101, quoting reference 43210239672.”