I fixed my tacho by snipping off a cable zip tie that came out if the stator. At first I thought the stator but the ohm reading was 38ohms right in the middle limits for a blue head, ( 35-40 ). I did a process of elimination so check the wiring, with a spare tacho I had wired up the grey tacho wire directly to the tacho ( I had to use a hell of a lot of electrical tape to the rear seat belt so I could see the tacho from start ). The problem still existed so the wiring in the aircraft is ok, I was thinking its gotta be that dam stator but the ohms are reading good what can it be. At this stage I was going to insure it then burn it..... just jokin!, At this stage I thought stator is ok wiring from the harness in the aeroplane is ok, so the wiring between the stator and the harness had a zip tie just out from the housing so I snipped that off then went out to fly thinking if it's not this I'm stuffed if I know, well I'll be buggered it's all good and linear now. I did get a little help from Glen Shaw at Dalby Air Maintenance.