I’ve replaced the wiring harness, and carb.

for starters the old carb was all gummed up and corroded.
Then my key switch fell apart and some of the other connections were all getting corrosion build up too so I decided to just replace it all for $35. Now, I’ve got it able to turn over and crank. But, I have no spark.

I back probed the pin on the top left of the CDI plug going to my spark coil. No voltage. I have good grounds and my brake switch is working. But for some reason I try to crank and I get no voltage on the yellow/black wire.

as you can see in the video it’s cranking nicely and I have 12.75 volts just can’t seem to fire.

I pulled the spark plug to see if it had any spark visually and I saw nothing.

I’ve tried two brand new 5 pin CDIs and two spark plug coil packs, and 2 spark plugs lol. Please help,
update: unpinned the middle pin for the shutdown switch, and the quad fired right up on the first try. Now what ?!

 

Also, just for clarification, I did test the spark plug outside the head and held the spark plug against the engine body for ground to watch for spark.

 

If it fires with the wire removed from the CDI it's probably one of the safety switches going to the front brake or tether. Do you have the 2 wires connected to the hand brake or at least connected together?

 

I have provided video feedback

 

video feedback in short yes, the front brake is connected.
In fact, the old wiring the atv started even if I wasn’t pressing brakes. But now I have a proper wiring kit, that’s “new”.
I also bench tested the actual kill switch and it is breaking the circuit as designed. So it’s not the switch for sure. It’s definitely one of my grounds or power sources.

 

The kill wire has nothing to do with the brake system. I note the awful "wiring diagram" shows a "flameout" plug at the rear end near the one for the rear light, this will be for the extra, sink plug or radio controlled kill switch. This has to be a suspect.

 

Are you suggesting that I connect that plug to ground instead of jumper wires? Right now, I’ve tried two ways
1st leave it unplugged and ignore
2nd connect them together and loop it.

What I understand your thought is to maybe, ground the ground wire, and leave the other wire unhooked to anything? Or?

 

No, if you leave the flameout unplugged it won't be earthed, so won't be the cause of your permanently earthed kill wire problem. My guess would be the ignition switch, if you can, disconnect the black/white to it and see if that cures the problem. It is just possible the old ignition system was earth to run on the kill wire, if so the kill button would work backwards and the kill part of the ignition switch would too, with your new earth to kill CDI, but you need ignition switch in the on position to run the starter etc.