I have just tried to sort the timing on my 69 KG and the numbers on my digital Tach just jump about all over the place. This has also happened when using it on my 76 Bay but I have found that if I turn the engine off and on I can get a sensible reading for a few minutes before it goes hay wire. I am connecting the red to the - on the coil and the Black to the battery earth strap as per instructions. Is my Tach faulty or is there another explanation?
thanks
Will