New they will run a little warmer until fully broke in...and long periods of sustained higher RPMs will always produce more heat especially as lean as these are running. Being in AZ I can't believe you have been doing any "Southern-style mudd'n". All machines will get their radiators plugged with mud when in their stock location. It just depends on how much you do, how deep you go and what type of mud it is. Just harder to plug-up mounted high. Just make sure the radiator is clear and full to the top with coolant..ie no air gaps.