hi ppl my nc30 is currently idling 2500 revz, it should be at around 1300 revz

can someone plz explain to me how i go about changing it back to 1300???????

and if my bike is idling high what are the damages????
besides fuel?

The idle speed adjuster is bolted to the bottom of the frame above the generator cover on the left hand side.
There may be an air leak if it is running that fast, but turn the cable screw out, anti clockwise, to check.

No real damage but gear selection will be more difficult, and I don't like to run cold engines fast

Also make sure the choke isnt on a tiny bit.... Again left had side of the bike just above the idle adjuster...