KZ305 Can adjust idle speed to 1k or 2k, but not in between

If I do a very touchy adjustment on the idle speed screw, I may get it to idle at 1300 rpm, but go for a long ride and it's up to 2,000+ rpm. If I adjust it at that time, it's idling too slow for short trip errand running. Also, when trying to adjust idle, it jumps from 1k to 2k with just the slightest turn of the screw. It's very hard to get it to settle in on a reasonable idle speed. 

Adjust the play and check the routing of the throttle cable. Next step would be a carb sync.

I have completely given up on getting my 305 to "carburate" properly. I just ride it. Might someday throw $400 at a pair of Mikunis, which I hear eliminate much of the fussiness of the CV-32 carbs. But I'd rather not.

Set the idle rpm when the engine is fully hot, so that, when the engine is cold, you can use the choke (mixture enricher) to increase the idle rpm until the engine is hot.

Un-like fuel injection systems, carbs cannot "know" the engine temperature, so they must be "set" (pilot jets, main jets, mixture screws) for an  engine that is at "opperating temperature".

H.