gpz750 going, going, not going?

Pic of the bowl would be helpful.
Steve

Your main jet size should make absolutely no difference at all to starting. Primary is next to the main correct.

On Cv carbs for cold starts you should never touch the throttle and just let the 'choke' do the work: opening the throttle cancels out the enrichment circuit 'choke'. Strangely, on mine it seems to like just a bit of throttle, also, unlike other kawasaki bikes it doesn't race really high on choke from cold.

Rich to begin with.
Steve