Z1OwnersClub GB

Now I've got my z1000a back together and running, I noticed that when I blip the throttle from tick-over to about 3000rpm, the headlight dips out for a fraction of a second. I thought I was imagining it at first, but with the bike in the workshop and the light shining at the door - it's noticeable and it does it every time. Is this normal ?
It's got the original separate regulator and rectifier, but they seem to be working fine, I'm getting 14.6v to the battery at about 4krpm.

try a new bulb bit obvious but sometimes !!!! or you may have a break in the wire thats separating at a resonance

Sounds like a possible bad earth / short. Maybe check the left hand handlebar switch / throttle ??