81 XJ750

So you can't have 480 ohms from the ignition fuse to the coil positive, it is not going to work. Perhaps it's a communication issue here and I don't understand what you are saying.

Be sure to check the pickup coils to ground also; the pickup coils should be open to ground

 

Ive fixed the issue with the resistance from the fise to coils. The pick up coils read 650 and 630 ohms of resistance to ground.
When I flip the grey and orange wire at the tci the spark flips.

 

OK, so now when cranking you have close to a solid 12V on both coils R/W wires?

The 650 to ground is OK if they are connected to the TCI and that's how you are measuring.

The troubleshooting guide suggests this, did you do this step?

5a. Switch the Orange and Grey wires from the pickups (6-position TCI plug) at the TCI. If the sparking and non-sparking pairs of plugs swap (i.e. if you had spark on 1/4 and not on 2/3 prior to swapping Orange/Grey and now have spark on 2/3 and not on 1/4) then you've got a bad pickup. If this didn't make a difference, swap the wires back and go to 5b.

If you don't get a swap suggesting a bad pickup and you have already done the coil wire swap then yes it would seem the TCI is bad. We often suggest the best test for a TCI is in another bike, or trying a known good one. Unfortunately, that is not always easy to accomplish. Could you have 3 bad TCI's, not likely but not impossible? Were they advertised as working units?

What is the voltage on the 4 pin orange and grey wires when the ignition key is turned on - remember the 3 second thing.

 

Yes I have good voltage on both red/white at the coils.
Ive done that step and rules out the pick up coils, when flipping the orange and grey on the 6 pin it makes no difference.
When I flip the orange to grey on the 4 pin the spark transfers to the other coil.

Im starting to think something on the bike might be frying that tci channel when I connect it? If so could it be a short somewhere? Leading to the tci, after towards the coils or both?

Because 2 in a row from a working bike seems a bit absurd to me. I got the tci's from know working parts bikes, off a friend who I know wouldnt try to screw me on something like that.

 

So the TCI is meant to drive a very low impedance primary coil, but that doesn't mean you couldn't damage one. However, to damage those output transistors you would pretty much have to short the ignition coil primary out, or apply 12V directly to the low side of the coil.

Odd that a working parts bike would have two TCI's, and that both were tested on this working parts bike?? If it is a working parts bike and a friend then just try them on that bike again.

I will ask again

And you could pop the cover on one of those new ones and look for damage like the original TCI where you found the burnt etch.

 

I will check the TCI's again on his bike, he's a motorcycle mechanic by trade and has a yard full of old bikes like that. TCI's didnt come from the same bike but he had one in a parts bin, another on a 81 maxim 650. From a quick look under the cover on the TCI's everything seems in order, no burnt smell like the first either.

I just dont know what would cause my no spark if not the tci. I know the wiring to the coils/plugs is good and I know my pick up coils are good