Misfire

[mikey]

Not an old Z but a GPz1000rx, start it up from cold runs absolutely fine,
couple miles down the road starts to misfire badly and rev counter needle
drops and rises with the misfire ? just started doing this yesterday,
leave it to stand for an hour start it up and its fine again until a couple of
miles down the road again.
My guess is something electrical breaking down when it gets warm.

[Pigford]

Coils are prone to failing like that when hot

Dunno if the clox are trying to tell you summink else

[mikey]

Exactly what i was thinking mark with the coils
but with the tacho needle behaving like that
makes me wonder if its the cdi unit ?

[zed1015]

Rev counter is triggered by the coils so most likely a duff coil.

[z1bman]

has it still got the side stand switch fitted? also plug gaps are prone to corroding look up inside the cap for corrosion as the plug chamber fills up with water

[mikey]

No side stand switch ill check plug caps.

Cheers for the heads up on the coils rob.

[Julian_Boolean]

Sounds like a coil is on the way out

[sid123]

check connections and condition of pick up coils on end of crank

[mikey]

Sid.... you were bang on the mark
wires to the pick ups had gone brittle and hard
and when they got hot were separating.

My brothers quite clever at fixing fiddly things like that
soldered in new wire problem gone