......you have located the actual MIXTURE screw??
My 1300 X has a 32DMTR Weber carb, and the mixture screw was initally hidden in its drilling location with a waxy sealing gunk (to prevent "non-professional" tinkerers from altering the initial production idle mixture/emission levels).
It takes a bit of searching to actually locate the idle screw, after probing away this sealant plug, and then using a thin bladed screwdriver to adjust the idle mixture.
If you have actually completely removed the TRUE idle mixture screw, the engine will stall!!
I kinda suspect that you are futzing with something other than the actual mixture screw??
Have a close look at the carb parts diagram in the Haynes workshop manual, or even better, in this Forum's online parts catalogue to ensure you are dealing with the correct adjustment screw.
cheers, Ian - NZ