I have about 10 n/c singles.I'm now retired, so for the next 5 yrs, the ones with no titles I will re build them with correct mags or alternators.
The ones with good titles will get alternators to have brighter lites to be ridden and enjoyed. Mag ingnitioned singles run ok, but have a terrible weak spark, and piss pore lites,that I wouldn' ride on the street. I couldn't afford all the dim lite tickets from the highway patrol,
6 Volt mag works ok as long as it in good condition-my 450RT starts easily and runs up to 8,000rpm with no missfires. I will stick with the mag since I don't want to have to lug a battery about and although I have (feeble) lights I don't ride it at night. Mine is street titled by the way so it gets used (and ridden on track!)-got a 2 day MiniGiro weekend after next.
The easy way with Ducati original coils is by color of the label, if there's any left. Red = DC (battery), green = AC (mag). That doesn't fully answer your question, but I'll look through my stacks for the resistance value difference, if I still have it.
The problem I am having is that the labels fall off after 30+ years and other than that, there does not appear to be any markings that would say a coil is AC or DC.
Having said that, I borrowed a coil that still has it's green label and I have a coil, that I am pretty sure is DC. Here is the resistence I found and would like someone to confirm or help us witht he correct resistence is.
AC and DC coil pin 1 to pin 15 (primary to ground) resistence is 2-4 Ohms
AC coil: primary to secondary coil (pin 15 to plug wire pin) (9K ohms)
DC coil: primary to secondary coil (pin 15 to plug wire pin) (6K ohms)
I am not sure what the numbers on the bottom mean, or if they can be used to differentiate between AC and DC coils.
I am going to run some 'field tests' this weekend with both coils, any thought would be appreciated !