When Keith Martin of Big D Cycle acquired a number of complete-but-rough motorcycles from the estate of a Texas collector, along with a large supply of NOS parts, his path was clear: Restore as many of the bikes as possible using the rare original parts on hand. The first two of those machines, freshly finished, are on offer here at Bonhams' 2015 Las Vegas auction. Big D in Dallas, Texas, is a 2008 restart of the famous Triumph dealership and speed shop run by the late Jack Wilson, builder…