I have an after market tacho (TIM, think it originally came from Demon Thieves) that I want to wire in but dont know what goes where. It has 4 leads, white, black, red and green. Can anyone hazard a guess where they all may go? Cheers.

Red is +12v switched supply e.g. +ve on the coil.
Black is ground.
Green is the ignition signal (-ve on coil with a conventional ignition system).
White is for illumination and should be connected to the sidelight circuit.