Hi guys iv got a nc30 vfr 400 and its idling at around 4k and the adjustment screw doesn't work! Is there any other way to lower it??

Cheers

are you sure the choke isnt on?

+ 1. Choke might also be stuck on at the carb end. I would also get a new idle screw.

Is the idle screw moving?

Choke stuck on?

Air leak? How's it run

If you, or someone else has turned the idle adjuster knob/cable too far anti-cockwise, the idle adjuster cable will become detached from the throttle body.
Also.....Choke cables can become frayed at either the carb end or the choke lever end which will cause the cable to jam.