Sachs Duomatic schematic.  Thanks to Marco the Sachs Duomatic Master for this diagram and an explanation for a common hub misassembly issue - below:  I assembled the hub without pushing the spring, part 19 through the hole, part 14.  And I didn't insert the wires from 13 into the slots in part 11.  The hub worked for a few yards or a few miles, then it just locked up.  Marco came to the rescue with the explanation below.

".....

25 - 13. It´s important that the part Nr.19 reaches with the wire into a hole on part 14. Also the wires of part 13 (14) must be reach into the little spaces of part 11."

Living Better and Longer - a 'howto' by a fellow cyclist

See Dan Buettner's interesting learning from his international cycling tours.  http://en.wikipedia.org/wiki/Dan_Buettner

Also, see his site: http://www.bluezones.com/

Sachs Duomatic - 2 speed kickback hub

Finally got one.  It came from a wonderful hub geek in Germany and it's in NOS condition no less.  I've overhauled it and laced it into a nice DT Swiss 700c rim.  Then I put it on my single speed and took off.  It was a perfectly smooth 2 speed bicycle ride for 2 miles.  Then the hub trouble started.  It just stopped turning as though I had applied the coaster brake. 

I'm looking around for solutions and will post on a few forums.  It's a rookie hub mounting mistake I suspect.  I'll bet my hub geed friend in Germany will have the answer!

Stay tuned