I'm hoping I can get some tips and advice on what I can try to troubleshoot this problem. I'm having a hard time adjusting the idle on a Kawasaki ninja 250. First bike, picked up used and took it to a shop for a look over. Nothing said about the idle or throttle, but there are 2 things going on that I feel need attention:

• It idles low, barely at 1000 rpm. It wants to stall sometimes at stops unless it is revving.

• Throttle doesn't snap back when twist checked. It rolls back slowly, but when riding it backs off immediately when let go.

I tried adjusting the idle, and now it will idle high after a rev, until I loosen the idle screw. A couple more revs and it will start to chug at a low idle again. Repeated the process several times, same results. It even revved up to a higher rpm and stayed when I was moving the bike back and forth to turn around, no throttle applied.

I feel I either need to clean/lubricate the throttle cables and idle screw, or maybe the screw itself needs replaced?

Or should I be looking at something completely different?

Any advice is appreciated. Thanks!