just put in a MT75 box and the speedo is electronic drive, anyone know the wiring sequence, which wire is what etc. I have bought an electronic multi do it all speedo rev counter thing and was wondering if I could tap into this ready made gearbox wiring

Black is 12v.
Brown is earth.
Yellow is signal out.

And yes I used it. Runs nice and smooth and no magnets to loose.

Your speedo will need to be able to handle a hall affect signal and not just a Vr signal.

[Edited on 11/5/17 by big_wasa]

many thanks for the info. Pleased to say I have it all working, bit optimistic with the read out, I'm now trying to work out how to use the recalibration instructions. Seems they are written in some Chinese code using appalling English, but I'll get there