Curvy rear cylinder loosing spark

[farquare]

Bit of a strange one this so here goes;

I had a problem last year where my curvy wasn't charging properly with the headlights on, i replaced the rectifier recently but haven't been using the bike much so I'm not really convinced its working properly.
To put my mind at rest i bought a little digital voltmeter, yesterday i got round to wiring it in and attaching it to the bike, i read that people were tapping into the rear light feed for a switched live so i did the same and grounded it at the front.

When i started the bike today the meter was giving out some strange readings, i hen noticed the rear cylinder wasn't firing.

I changed the coils round and managed to conclude that both coils and both plugs were good, but stll no spark on the rear cylinder…… .
As a last resort I disconnected the voltmeter and as if by magic the rear started firing again… ..

So the question is what have I tapped into at the back then, from memory there appeared to be 3 switched lives on the big connection behind the tail light, I think I went for the one in the top corner..

Any thoughts?
Thanks in advance

[farquare]

Thinking about it this morning the wire I spliced into (white with a red tracer) might be a similar colour to what supplies the rear coil.

Is there a simple ecu on a curvy controlling advance/retard on the timing, if so does this reside at the back of the bike?

Sent from my SK17i using Tapatalk 2

[farquare]

Looks like I've tapped in to the orange and white feed on the ignitor circuit..

Will back that adjustment out and use the attached wiring diagram…

http://www.motoinfo.yoyo.pl/Suzuki/S...pg?ckattempt=1