Check the various online suppliers, but you can also put an automatic search function on e-Bay. I have used it several times, to find parts. It will automatically troll through the listings for you, searching for matches to your search criteria. I found a NOS set of engine guard bars, for a 1983 Kawasaki 440 LTD, which were 26 years old, still in the original packing. It's amazing what pops up on e-Bay. Best of luck. Cheers!
1979 CB750K (sold, 2012, but not forgotten)
1983 Kawasaki 440 LTD Belt Drive (sold, 2011)
1993 Kawasaki Voyager XII