Just trying to put the wire for the tacho on the negative terminal of my coil (the yellow wire). and when i do this i don't get spark, Ive checked my coil with a multi meter and I'm getting 12 volt on the pos and neg of my coil. Why am I getting 12 volt on my negative on my coil. and where should a put the wire to run my tacho?

Heres the link for the wiring of the xr3000 http://www.cranecams.com/uploads/ins...9000-0700_.pdf