If it's got a differential and electric start, I'm guessing it's probably a Big Red. Other members on here will be able able to help identify which model it is better than I, especially if you post up some pics.I know there is a link to an ATC VIN decoder floating around here somewhere, but I don't have the time to find it for ya. Do a search and it'll probably pop-up. Also, click on the tab to "Old 3WW" at the top of this page and you'll find all kinds of useful info, such as Honda ATC specs for all years & models, and full color brochures as well. If you still can't find your manual, if you ask MonroeMike nicely enough he may be able to provide a free manual download for you.
Current trikes owned:
1985 Yamaha Tri-Z 250...fully restored
1985 Honda 250 SX...nice survivor original condition