Some great comments there guys, I feel much more the wiser and now understand it all more. I shall give suggestions a go tomoz.

Because the tacho is off another model, then it may be possible that its set for a different kind of pulse from the CDI and not that of a CBR. The tacho was from a VFR which is a V4?
I will let you all know of my findings. Who ever messed with the current wiring loom needs shooting! Thanks again. I determined to beat this problem lol.

 

Ok, I have checked the pulse wire from the CDI, on idle it's putting out 1.5V but when you rev the engine it goes up accordingly, the most I saw was 5.5V?

Next I will try wiring it up on LT side of the coil. I did try this before but will try the other coil. It did read last time out but only about a 1/4 of revs it should be reading.

 

Have you tried contacting the manufacturer and asking for the technical data so you can at least know what you're looking for?

 

I guess I could call the local dealer and ask. I wish I had the standard tacho just to clear up a few things or a donor CBR600 for cross reference.

 

I have a hunch that the tacho is dead. I fitted my old mini electronic tacho to the yellow & green pulse wire from the CDI and the tacho worked fine from there. So it must be the tacho. I will buy another set of CBR clocks from fleabay, maybe the 900 fireblade ones will work.

 

Told ya so.

 

I'm not eating humble pie just yet, and new tacho will tell the tale. If it's the old tacho I will throw it as far down the road as possible. I have spent days trying to diagnose this problem lol.

 

Just bought another set of VFR400 clocks from fleabay. I will try them without taken them to bits this time. If they do not work at least I can throw them back on!

 

Well wired up the new set of clocks and guess what? Nothing again. The needle does not move at arrrrragggghhhhh.
I have studied both manuals the VFR & the CBR. My findings were for the CBR;
The tacho only appears to have two wires. Yellow & Green (CDI Pulse) and green (earth) and no live 12V DC wire?

The tacho on the VFR has 3 wires, Yellow & Green (CDI Pulse) Green (Earth) & Brown & Black (Live 12V DC)

I'm gonna try one more thing... I will try wiring the pulse wire from the tacho to each terminal of the coil. One of the four terminals has to work???