Denmark police are investigating a serious motorcycle crash which has left a 49-year-old man in hospital in Perth. About 9.30pm on Friday, police were called to a crash on Sheoak Drive in Hay, where a man had been thrown from a motor-cycle. Denmark officer-in-charge Sgt Matt Hartfield said the rider was travelling south-west when he failed to negotiate a bend and struck a tree. The injured rider managed to call triple-0. Paramedics took the man to Denmark Hospital before he was transferred to Albany Health Campus. From there, he was flown by the Royal Flying Doctor Service to Royal Perth Hospital with fractures to his leg and back. He was in a stable condition at RPH yesterday. Police are investigating whether speed or alcohol were factors in the crash. Anyone with information about the crash is asked to phone Denmark police on 9848 0500 or Crime Stoppers on 1800 333 000.