What might cause a reverse reading such as you are thinking ?

Hello Everyone,  I couldn't wait till morning , its a simpson model 467 true RMS Digital multimeter its an old one but well cared for . It's a push button thing  ohms button is pushed in when I start the meter is reading 1 . , When I touch the probes together it reads 0.00 . I tested a new key switch by touching the black probe to the black wire in the 4 wire plug and the other probe to the black /white wire in the plug when the key is off, the meter reads 0.00 when I switch it on it
reads 1. , 
I tried this on the switch on the bike the same way as I did on the new switch and the same thing happens I tried it a bunch of times and same thing on both key switches .
I tried it on the new 2 wire kill switch , black probe to black wire, other probe to black /white wire switched up to off got 0.00 switch down to run got 1 ., 
tried the same on the original 1 wire kill switch , touched black to ground handlebar contact inside rim of switch housing that touches the handlebars , other lead to black /white wire switch up off 0.00 switch down to run position  getting a reading of 1  .  , so everything I did involved black and black/ white wires two kill switches and to key switches I got the same results on all .
I also did what deet said to test touched one probe to crankcase and one to bare metal on the footed lug  and got a reading of 0.00  he said it should be less than 1 . 
am I doing the test correctly?

As always any help greatly appreciated .
thank you
John

The black / white in the headlight from main harness is plugged into black/white from the New 2 wire kill switch and black is plugged into black triple from main harness , the black from the tach is plugged into black triple from main harness and idiot light blinks when turn signals blink. Front and rear turn signals blink when key switch is on and the front must be grounded thru the handlebars since there's no ground wire like the rear ones have attached with ring connectors and plugged into the triple black from main harness near the battery so they must be grounded correctly or they wouldn't work ,Black from tail light is plugged in triple as well I think .
The horn works when the key is on ,the front and rear brake switches work when key is on, the on off switch works for tailight works when key switch is on , (still a little foggy on that one with 2 position key switch and tailight but switch does turn it on and off ) everything but key and kill switch works , bike seems to run very well when the gas flows from the spigot that's another thing that's boggling me the spigot will flow good when the hose isn't connected but when it is connected sometimes it won't flow on reserve only a trickle until it's running then it seems to flow better , trying to jamb as much info in as I can . Can't think of much else my head hurts good night to all
John

I'm not up on the play with digital meters but thinking '00' means open circuit & '1' means those two wires connecting to each other?.
That's if we're talking ignition wires for off & on at ignition switch which i'm thinking are Black then a Black/White. Black/white needs to head down the Black when off to ground the B/W.
I'm not thinking too straight tonight so happy to be corrected.

Hi RT325, thanks for your reply , this wiring business is wicked confusing to me , dont know if i was testing correctly . it's got to be something simple stopping the kill and key switches from functioning . I've gone back and re read what you guys said and I'm going to again .
I'll keep reading till an answer is found.
Thanks again
John

I have a 75 DT250 that previous owner removed the wiring harness from.  Should be very close to your 1974 wiring, if not identical.  I will try to find the harness and take pictures to explain how the kill switch works and how to troubleshoot.

P.S.  That's a nice meter you have...  and your switch test description is very good!  The readings you're seeing are what I'd expect from a properly operating kill switch.

 

Thank You MarkT,
I appreciate very much what you said! And the effort that you are making. Your a Good Man!
I had a thought about my key switch when I initially got the bike many years ago someone had hacked the key switch wires it had a key in the switch , so during this build I ended up buying a speedo and tach from ebay that was from a 76 dt400, it was a complete set up key switch and all the wires everything , it just didn't have a key , so I took the top half from the original key switch that was on the bike and removed the top half , just the key part , none of the other parts inside the switch and installed it to the lower half of the 1976 dt400 switch and utilized the guts and wires from the dt400 , I had to change the plug end because it wasn't spades it was pins and wouldn't fit my new harness . After looking at partzilla part numbers from the 74 dt250a and the 76 dt400 the part numbers are different and the 74 dt250a keyswitch is only for the 250a and the 360a , so what I'm gonna do is take the switch apart and compare the two contact plates and if their different I'll unsolder the connections and soulder the wires back on the contact plate from the dt250a which I still have . If I'm right would that affect how the kill switch works?
Thank you very much for your time and patience
John

Like I said, the "kill" circuit is working as expected!  Nothing else in the switch has anything to do with killing spark! 

Please don't mess with the key switch yet.  It's not likely your problem at all.  If it was, your handlebar kill should still work as it's completely independent of the key switch. 

I think my DT250 harness is out in Pahrump...  about 70 miles from here.  I'm heading out there now to get it and hopefully by tomorrow I will have pictures that will help you find the issue. 

I just compared the two contact plates they look identical but the dt400 little round copper contacts are very worn compared to the original dt250a contacts, actually there is a slight difference on the backside of it where the wires are soldered on, the red and brown  very slight difference in how/where they soldered it. the black/white  and black are the same on both contact plates.

I appreciate you pointing out how the key and kill are independent of each other