Won’t run on all cylinders

[gray]

Something else worth checking while you're awaiting inspiration
My z900A4 has a low speed running problem for ages, just as you picked up throttle. Cleaned the pilot jet circuits again and again to no avail. Turned out the the advance /retard unit springs were stretched, so as the throttle was opened, it went to full advance straightaway and stuttered till you got to 3k revs
Compressions ok?
Is the cam timing OK ?

[Mr Bump]

Sounds like you need to start at the start to me:

1 - compression test, check cam timing and valve clearances.

2- probably worth buying a set of pattern coils as they ain't too expensive, new ht leads and plugs, go through the whole ignition wiring against a wiring diagram, try wiring the coil lower tension positive straight to the battery to eliminate poor voltage supply through a knackered loom or switches (don't leave the coils connected to the battery when it's not running as you'll fry yr new coils) , test the ignition pickups against whatever factory spec is. After every change to the ignition system recheck to see if you've fixed it or introduced a new fault, only change one thing at a time.

3- hopefully yr man will rebuild the carbs correctly. When you get them back hook them up one of those Sealey header tanks (not yr rusty tank) and only use fresh petrol, not whatever is in the tank or something lurking in a can. If it runs somewhere near right balance the carbs and hopefully you'll be there.

Hope this is some help, a bit of a drag as it's a lot of jobs to work through but it is winter now. Every thing you check and eliminate is a gain, even if it seems unlikely or a pain.

Gents, if I've made a mistake here or missed something please do wade in and correct me.

Olly