KV75 ignition problems - no spark

[my67xr]

are you able to put a pin into the lead to touch the core, about 1" back from the end of it.
and try measuring it again, i'm wondering if it has a break maybe?
if you get a reading then trim the lead back if it's long enough to.

 

[Pacoperryz]

Took an inch off the lead with my wire cutters. Same result...
Question. The 2.4 ohms across the primary is repeatable but only if I have the black lead disconnected . I only get 0.4 ohms if the lead is connected. Makes no difference on the secondary. Meter doesn't even flinch, lead connected or not. Looking hard at ordering the 70's vintage coil on eBay

 

[Pacoperryz]

Took an inch off the lead with my wire cutters. Same result...
Question. The 2.4 ohms across the primary is repeatable but only if I have the black lead disconnected . I only get 0.4 ohms if the lead is connected. Does that tell you anything? Makes no difference on the secondary. Meter doesn't even flinch, lead connected or not. Looking hard at ordering the 70's vintage coil on eBay.

Out of curiosity I took an razor knife to the 1" section of spark plug lead to open it up. Sorry for my ignorance but you mention the 'core'. Nothing looking like a core in it. Just copper filament wires (7 individual strands)

 

[my67xr]

the core of the coil lead is the wires,
sometimes made of copper strands, solid copper, stainless strands, twin solid core, wire wound carbon core etc etc.

 

[my67xr]

i dont understand what you mean by only getting a reading with the black disconnected though?

 

[Pacoperryz]

With the black wire disconnected from the coil, I get 2.4 ohms across the primary (one electrode one the black wire into the coil, other electrode to earth). If I connect the wire to the magneto as per the wiring diagram, I get 0.4 ohms across the same two points.

 

[my67xr]

yeah ok, that's how you need to test it.

do you have an Analogue multimeter, sometimes you can get funny readings with the auto/digital meters.

 

[Pacoperryz]

Unfortunately do not. Taking a flyer on the used coil and hoping that works.

 

[Pacoperryz]

Soooooo.....new/old ignition coil arrived today. Anxious to give it another go, I swap out the other brand new one and hook up the multimeter. Damn if I still don't get ambiguous results with the primary resistance all over the map and the secondary resistance non-existent. As my67xr pointed out, I think my digital meter has issues. To hell with it, I decided to wire it up and give it a try. I get it off the work bench, start stroking it.....and nothing...what the hell? Check out my spark plug wire and what do I find? My new/old ignition coil plug wire has a splice that came apart. Reattach it as best I can and cross my fingers for one more go. The result???

SUCCESS!!!!!!

Loving all the looks from neighbours looking out their window at 8 pm as i give it lots of revs! After several months, a new spark plug, a flywheel puller, new points, new condenser, a quick fix on my magneto coil, two replacement ignition coils, and weeks of waiting on shipping in between most of them, it turned out to be the part I suspected from the beginning. Oh well, I guess perseverance pays off. Feels good to finally get to bottom of it. Now to clean it up and move on to the other more minor issues to make this bad boy road worthy.

Thanks my67xr for all your help and guidance. Was seeking help on 2 other forums as well as this one and you were the only one to give me any serious help. Much appreciated. :applaudit: