Points closed should have a "0" reading.  Sounds like your points are not making good contact somehow?

My DT3 Enduro was giving problems running and starting, caused by a faulty source coil. 
Eventually I fitted a 12v system with electronic ignition. No more ankle breaking kick backs and easier to start. It's a Vape system. 

Thanks, I installed the Vape system on my DT400, worked good until I made a stupid mistake and had a runaway throttle that caused the flywheel to spin because it doesn't have a woodrif key (not sure how much), on the crankshaft, now I can't get it started so it's been on the back burner for over a year.  I'd like to keep this 6v for a couple of reasons...  Thanks again.

Any hints on where to start looking, should I pull the stator off? 

I have been following this thread, and just read through it again to be sure, your first post was you had spark but lost it, was it running and driving when you lost spark?
If I was in your shoes the very first thing I would do is try a known good spark plug, much easier than some of the more in depth troubleshooting you are trying, in my mechanical experience many times it is usually something simple, but I try and always get as much information as to what was happening before the failure, much easier than trying to guess.

Did you ever find out why with points closed you didn't have zero resistance to ground?  That seems like the place to start. 

Thanks for the reply and suggestion.  Yes it was running when I lost spark, it sputtered/back fired through the exhaust then died.  I have tried three different plugs, one is brand new.

Good morning Mark, no I haven't figured that out.  I guess my last message was a bit vague, I don't know where to start to trouble shoot that, staring at it hasn't worked

Like I said earlier, if you don't have zero resistance with points closed it sounds like the points aren't making good contact. 

Cut some strips of white uncoated business card or equivalent card stock...  you need something that doesn't "tuft" easily...  Close points on a strip and pull it through closed points.  Repeat with new strips until card stock comes out clean.  All it takes is a tiny bit of grit or something to keep points from making contact.

Also best to test black stator wire to points with it disconnected from harness.  Points closed you should have zero resistance.  Points open, usually have 1 to 2 ohms.  If you don't, no spark.  Also many digital meters bounce and hard to get good readings.  An analog (swinging needle) meter with an Rx1 scale like Yamaha used usually works better in my experience. 

Thanks Mark, I'll give that a try in the next 2 or 3 days after I recover from laying laminate in my living room today...