Motorcycle Questions? Ask a Mechanic.
Hello, couple of things to check
1. Unhook the throttle cable and manually rev the carb at the carb linkage. If it idles back down properly you know the cable needs to be replaced
2 if it doesn't idle back down look to see if it's closing all the way like it should when you let off. if not it's either a binding throttle shaft or worn return spring on the shaft
3. if both of the above check good spray around where the carb is mounted with some carb cleaner to check for vacuum leaks. a vacuum leak will make it overly lean and cause this.
Let me know what you find and we can work further if needed.
Glad to hear it's straightening out some. I'm glad I could help.