Riley's former chief of staff, Dave Stewart, said it happened Sunday afternoon on a dirt and gravel road near Fairbanks. It was raining and the former governor "had to lay the motorcycle down" to avoid losing control, Stewart said Monday.
Stewart said Riley was being treated in a Fairbanks hospital for several broken bones and a punctured lung. He said doctors expect Riley to make a full recovery.
Former First Lady Patsy Riley and Riley's son, Birmingham lawyer Rob Riley, were planning to travel to Alaska this week to be with the former governor.
The Alabama Republican was on a long planned cross-country motorcycle trip from his hometown, Ashland, to Alaska.