To start off with here is a few links with some interesting reading and history.
The Tale of the H1:
http://www.mcnews.com.au
Restoring and Remembering the Kawasaki Triples:
Motorcycle.com Triples Article
History of the Kawasaki Mach III and Mach IV:
Motorcycle Hall of Fame Article
So for those who don't know about the Kawasaki Designations-
Kawasaki 500cc triple = H1 = Mach III
Kawasaki 750cc triple = H2 = Mach IV