Thanks chaps, but after repeated failings on my part, I saw sense, and sent her to Oz at Zed Parts to help rid the gremlin.
Honestly no matter what I did she was not having any of it.
Pete, my real issue was not being able to correctly balance / sync all 3 carbs at the same time - ive done it many many times, but not on the Z13. Narrowed it down to the centre carb: Engine Compression at 175psi - good coils - strong spark - timing spot on - carbs appear spot on - etc etc. Buit almost like I could not get a vacuum, but I have no leaks anywhere, and everything else looks OK.
Spoke to Oz the Z13 Meister, and he says he's never seen anything like it before and also is having challenges setting my bike up: so I dont feel such a numpty.
Would really like to get my bike back on the road before the crappy weather returns.
Cheers Tim