I have a 2007 Kawasaki Ninja 500ex and I am having a problem with the bike idling. When I am warming up the bike with the choke engaged, it runs fine. But when I close off the choke and say that, for example, I am waiting at a red light, a stop sign, or I am in park, the bike will bounce up and below 1,000 RPMs. I almost sounds like the bike is on the verge of stalling out and chugs. When I give it gas and I start moving at 10 or 65 MPH, the bike runs flawlessly. I just have a problem with the bike idling. It started doing this right after I washed it and I also rode the bike in the rain.

The bike has been taken care of with oil changes and the chain has been lubricated. There are 9,000 miles on the bike and yes, it has been rode hard.

Any idea what this could be? I am hoping it isn't the carburetor because I understand that this can be a rather expensive fix.

Thank for the help.