the exhaust pipes should be the same temp... clean the contact pins for the thermostat.. if you remove the thermo stat check its operation by putting the probe in boiling water should trigger it to work.
Back flush the radiator if stood around and not run for awhile, checking for leaks and any hot cold patches on the radiator. The bikes generally get hot quickly & normally the gauge indicates mid way on the scale.
If this bike been off road for a while when you test it on the road check the temp of your disc brakes are they all same temperature, discs should be between 4.5 and 5mm thick.