The latest issue of Mitch Boehm's Moto Retro is out, and included is one of the most amazing articles on the Honda ATC, and how the whole thing started way back in 1969 or whenever it was.
Do yourself a favor, get this magazine.
It is 12 pages of ATC history with some amazing photos, and a cameo from "Vintage" Mike Palmgren, owner of Vintage Motorsports, and about the only man on the face of the earth to (re)build bikes for Honda of Japan.
The story covers how Honda came up with the idea, and how it was launched, and the early years of the ATC. It is a really good read.
Order a subscription and support those guys, the print media business is tough, but this one is well worth your time:
http://www.motoretroillustrated.com/
I know Mike is sometimes on this site, so maybe he will chime in and add some details about the story. But is very cool and very well worth having in your collection.