hello,
I have a 93 cbr 600 f2 and the rpm's changes sitting idle. they just goes up and down without me throttling it. it happens mainly when come up to a stop sign/ traffic light. please advise.

thanks

 

More information please.

Did it just start doing this?
Does it do it when the choke is on?
Has the bike been stored a while?
Have you recent done any work on it?
Do you ever smell fudge when there isn't any fudge around?

Might be running lean. Could be a vacuum leak, petcock hose or cracked carb boot, or plugged carb.