I bought my 650 a couple weeks ago and have been looking around at different forums for info and this one seems to be the most active with regards to our bike. Tons of good info.
Anyway just thought I'd pass on a piece of info I thought might be helpful. During my first ride my quad started overheating and overflowing coolant. Got home and started checking things out and found one of the wire connectors that goes from the radiator sensor that controls the fan had come disconnected. The two male/female connectors on the radiator were extremely loose. Just crimped the female ends down a bit and plugged them back in. Problem solved. Didn't even know it had a fan until I got to poking around.

 

The fan on my Praire ran a lot and seemed to run warm. I put a thermostat from a Kawasaki mule in it and the fan runs much less and runs cooler.
Bearman