Ever think that the temp gauge may be reading a little high. It may be old too. Also keep in mind this is a basic cooling system.
Technically all metering devices should be calibrated or checked every so often. When I was in the military, every critical pressure, vacuum, digital, temp, dial indicator gauge was calibrated on a regular basis.
A true case of overheating will have the thermostat at full lift and the radiator cap releasing coolant into the reservoir and the fan running.
"Many bikes engage the fan just below the red zone, while others have been reported engaging the fan at the mid-way point on the temperature gauge. The most important thing here is that it's entirely normal for your bike's temperature gauge to run all the way up to the bottom of the red zone before the fan comes on." ~
http://faq.ninja250.org/wiki/Cooling_system