Odd spark problem

[Svsam]

Evening all, 

I’m having a bit of headache with my recently turbo’d 7/12 project. 
Got the tank back on her this morning, excited and fired her up, went round the block no problem. Happy days. 
 

Then I tried to start it again and nothing, checked the spark plugs which are new and no spark...

but it did spark if I held the plug about 2mm off the block, if it touched it’d not spark, take the contact away slightly and it’d arc to the block and spark 

 

luckily I’ve got a bit of a collection here so I’ve been trying a few bits.

ive swapped the coils first, no change.

swapped the plugs, no change. 

swapped the pulse generator, no change. 
 

so thought I wander if there is a positive current running through the frame stopping the spark ( I know I should have been a sparky!) 

so it seems there is 0.01 volts through the frame, only when the ignition is on. 
is this the problem? Am I looking for a wire?

 

I ive tried the searches but what the hell do you search with this??

Cheers y’all 

[Svsam]

Oh and here’s a piccy so you don’t think it never happened 

[Oilyspanner]

If the other electrics work  that are negatively linked to the engine/frame, then all should be good. I've had a couple of problems in the past that were caused by the low tension wires at the coil flag terminals fracturing - sometimes the spark was good and other times I had no spark when the wire moved, the plastic sheathing hid the break in the copper wires underneath - it might not be this, but worth a check. The wire on the flag terminals that attaches to the coils get twisted a lot when putting them on and off, causing fatigue/fracture. I checked for continuity by disconnecting the ignitor connector, linking each end with the multi tester and wiggling the wire - continuity kept disappearing - the break was just before the crimp. Hope you find the fault.