Are you sure of the 1100's year? It's probably an 81 or later.
Measure the distance between the frame grip mounting points then ask the seller for the same measurement. Also, note the geometry of the mounting points --- whether or not they are in the same line. And note any other fitment issues, such as tail light or rear seat cover clearance.
If the 1300 doesn't fit, you can find K&L universal fit luggage racks all over eebbaayy. K&L, KL, K L, etc. They're listed in all sorts of ways, often times depending up what bike they were on: CB750, GS850, CB900, KZ1000, etc Most are in poor condition, but a decent one or two can be found... if not now, eventually.
