Paughco, Kiwi Motorcycles, J&P to start with but you could just google either term (i.e. type motorcycle+girder) and parse the results, there'll be plenty. Here's a Dufree Girder to view:
A positive attitude may not solve all your problems, but it will annoy enough people to make it worth the effort. Herm Albright (1876 - 1944)
