Help with CRAZY REDLINE rev given no throttle?

I have been trying to get my 1974 Cb360 to idle.

What happens is that when the throttle stop screw is disengaged totally it wont idle at all. Starts then dies with no throttle. Can keep it running with a little throttle. No over rev.

I give the stop screw like half a turn and the bike revs to the moon. Very sensitive. It's like its either on or off. Its not the original set up for the stop screw. I had to replace that with just a regular screw that turns with a screw driver.

When it revs like that it backfires through the carbs and the pipes, smoke comes heavy from the breather tube
and points cover and the carburetors have a little fit and start jerking around.

I have to kill the bike with the choke.

It is like when it gets to a point where it wants to idle is when it will take off like a crazy bike.

Last night I let it rev and tried to adjust it a little but that is when it started smoking like crazy. Got nervous and shut it down.
Could I have burnt the crap out of one of my pistons letting it rev like that?

Anyhow, what could cause this.