YUKON — A man died today when a bucket lift truck on which he was working tipped over in Yukon, Canadian County Sheriff Lewis Hawkins said. Kenneth Martin , 26, was pronounced dead at a metro-area hospital, Hawkins said. About 6 p.m., Martin was in the truck’s bucket behind a Shell convenience store at Interstate 40 and N Banner Road when he started to check the operation of the bucket and its arms, Hawkins said....