Will only start using starter fluid

Hi everyone.
Newbie here but I've been looking in on the forum and picking up great advice .
I'm currently restoring a 1977 kz650 c.
I'll be putting up pics soon but I'm having one major prob with bike .. and hopefully I can get some answers here.
On cold start the bike WILL NOT start unless I use starter fluid ( I'm using carb cleaner ) ...once started it runs fine ..ldles good and will start again first kick or tip of the starter button. Pulls like a train and revs good....
It's the initial start up is the only prob.
I haven't pulled the carbs yet but I'm suspecting this is the prob? Or choke maybe ??
The airbox is removed and pods installed and I'm not sure what size jets is in the carbs..
Hope this is enough info .
Thanks in advance folks and look forward to your input
Thanks
Ken

Check valve clearances and compression.

Ist not a choke system at cold start, it´s a extra fat air/fuel enrichment circuit/jetting.
Pull the carb bowls and clean the starter jet and starter pipe.

Thanks a mill . I'll try that as soon as I can .