Erratic Idle

Just finished a resto on my 75 Z1B, went through the carbs , problem is the idle will hang up after revving it up,starts fine with the choke but won't idle 100% then revs up, new manifold boots and the carbs work good on my buddys Z1R and his carbs act the same on my bike so it seems like a vacuum leak but didn't do this before the restoration. No changes to the engine except Dyna coils and ignition and I can't get the ignition timing to fire on the F mark. Advance works , set full timing about 28 degrees but when the idle slowly comes back down timing sits on the line ahead of the F mark,when I dial the light back it's about 3 degrees out, moving the breaker plate isn't helping.
Must be something I'm missing...

Old carb boots? ...between the carbs and the head. Spray some starter fluid around that area and see if the idle changes. If so, that's where your vac leak is...

Based on what you wrote I would suspect the return springs on you advancer. Could be hanging up somehow. Another thought is the Dyna is set for 1/4 but 2/3 is off or vice versa. I am installing a Dyna on mine but haven't gotten to timing it yet. Just some ideas. Good hunting, Keith

Carb boots are new but I'm going to look closer at the advance springs...

I would guess springs aswell But if that cheaks out take a look at the choke plungers.

ordered new caps for the choke plungers,haven't installed them yet but when I installed my carbs on my buddys running Z1R they work fine just out of sync a small amount.