Poor idle and jerkink under acceleration.

[Lyndon]

Hi, I'm Lyndon.
I have a 2001 GZ250 that seems to take an age to drop back to idle speed when the grip is released. It also jerks as I am accelating through the gears. Engine speed seems generaly slightly unstable. I've checked the throttle cable operation and it looks ok.
I'm hoping that someone can point me to a solution or al least somewhere to look. I'm thinking fuel mixture in the carb and I'm planing to strip and clean it, but I'm really only guessing. Any assistance would be appreciated.