zed1015 wrote:120 mains is miles too big with airbox and will be drowning the motor.
Should be 102.5 to 107.5 depending on year so start at 107.5 and work down.
Once fitted if the problem still persists and the pilot circuit is definately clear then the issue might be tuned out on the pilot air screw.
To determine whether you have a rich or lean condition causing the hesitation simply feather the choke (enrichener) at the point of hesitiation and if it improves you are weak and if no change or it worsens you are too rich.
Also having 120 mains fitted means the carbs may have previously run with K&N filters or stacks.
This may mean they are also fitted with air corrector jets which will over richen the bottom end in this situation and will need removing.
If this is the case they will clearly be visible in the mouths of the carbs in the form of a slotted brass screw.
Much appreciated - it did have K&Ns fitted when I got it, after a 12 month rebuild I’m really happy it’s running smoothly but would like to reset to ‘standard’ which is probably a z1000 a1 spec. Any recommendations as to where to get the bits ?
Also with the air screws there’s no noticeable increase in RPM - if the screws are turned completely in the bike misses a bit but once out about one then it’s runs smoothly but no real increase in RPM