I received a letter from "bul74", the seller of eBay auction # 290150783185,
"ARD Magneto Honda CB750 SOHC Cafe/Chopper",
(which was won by "hotrodcarpy" ) . It contained a copy of an instruction sheet for the auctioned magneto (Thanks Again, Jeff!)...but it is not clear whether the instructions are for an ARD, a Yoshimura, or a RC Engineering magneto...and also a copy of that March 1972 Hot Bike magneto article (page 4) that I posted earlier...small world, isn't it...
The copy of the timing instructions was very good, but the magazine/book the instructions came from was not given, so I guess we need to treat these instructions with caution...
If anyone has a problem reading the timing sheet (PhotoBucket may have resized it), I transcribed it and can post it if desired. The instruction sheet almost looks like it came out of the back of an early Clymer manual...Can anyone confirm this???