aussie_biker wrote on 12/31/69 at 16:00:03:My bike was doing that too.Everything seemed to work but no spark.New coil & cdi = still no spark.Then discovered wiring not quite connected in handlebar switch.Fixed that then nothing worked at all.
Found by holding horn switch & playing with earth lead from battery it would work.Hopefully new earth lead will sort things out.
Sorry to hear such tough luck there bud. Ground (earth) problems are the bane of working with electrons running anywhere down a pipe (wire). Thankfully on bikes we mostly deal with DC circuits and don't have to worry about ghostly problems like ground loops which can cause noise or be downright deadly in some electronic gear. One of my other hobbies is working on and building tube type guitar amplifiers, and it sometimes stuns me how some 'old' designs worked so well, and yet a supposedly modern 'star' ground design can give you fits with noise.
Hope the new ground wire solves it all for you. I certainly have personally known it to be the source of all kinds of weird problems on vehicles with more than two wheels.