Hi all.
I'm currently nearing the end of a year long restore of a 1975 DT250 and am now struggling with the stator and points. The coils test fine (with resistance on the high side but probably okay), and I've installed new points to replace the old, extremely corroded one. The problem as I understand it, is as follows. When testing the circuit flowing from the black wire on the stator, the points opening should break the circuit (and make the beep stop on my meter). However this isn't happening. The position of the points, whether closed or open, seems to have no impact, the circuit remains closed and grounded. Now my question is what could cause this? An errant ground? A bad coil or condenser? Or am I misunderstanding something basic and testing it incorrectly? Apologies for any misuse of terms, the electrical side of this restore has undoubtedly been my weak side. I've included pics of my overall progress as well as the stator in question. Thanks guys! 

Your understanding is the issue.  This is a magneto, not a battery ignition.  Points closed should have zero resistance.  Points open 1 to 2 ohms resistance which is the resistance of the stator source coil.  Some continuity buzzers might change tone slightly when points open, most won't. Old fashioned analog ohmmeter with Rx1 scale is the best meter...  or the Cadillac of tools is a specialized Aircraft Magneto timing tool which uses the change in inductance to turn a buzzer and light on and off as the points open and close.

Tons of posts on this topic if you search. 

Perfect! Thanks so much for the response!

I had a genuine yamaha points meter years ago & regrettably let it sit with a C battery on board for ever after cdi ignition arrived & the rotten battery destroyed it. Was a super low resistance & the needle moved from ';guessing now' hard over red then back heaps to green. Anyway--was great in its day.& here we are back there again.

For some reason i cant save the pic to expand but smaller coil is ignition & looks like a wire also going to other coil from condenser. Where's that green go. Must be me--don't worry.

For me the best and reliable is a 6V bulb.
Black wire from stator to bulb to battery plus and battery minus to ground
The bulb is always on, but rotating the crank, you will see getting the light darker/brighter at the opening point.
 

I have to agree with WESSI.  The 6 volt bulb method worked well for me, once I figured out how and what to check things with it.  Just solder your wires to the tip and side of one of the nice larger 6 volt turn signal bulbs and you've made your testing "tool".