poor idle

Hello, I am currently facing an issue with my bike where the left side is not firing while at idle. I noticed this when I touched the exhausts and noticed the left side was noticeably colder than the right, so when I pulled the left spark plug boot while running, there was no drop in RPMs...

Trying to set my idle speed and air screw on my keihin carb, but cannot before the bike dies, will start up again once, and rather poorly. Checked the spark plug ultiple times with multiple plugs and they have a large amount of carbon build up each time. Does anyone have a cb125s, and are...