07wr250f

I have the same bike and I haven't experienced anything like you are describing. When starting the bike with the choke on, I only need the choke on for about 30 seconds or less before it will idle at a regular speed (choke off). Have you looked at the carburetor to see if any of the jets are gunked up? As far as I am aware the bike should not have any of the idle issues you are having. Cheers and happy riding!