Your Sportster is air-cooled , and may run hotter then some other bikes, but it should not be "over" heating. what are the symptoms that make you think it is too hot?a lean condition will cause it to run hot, and to a lesser degree, So will an overly rich motor. Timing could be off, either valve or ignition, usually ignition timing. inadequate oil pressure.,from a bad oil pump, clogged line or filter.even excessive idling or low speed riding or lugging the motor could cause the temperature to rise above normal. We really would have to know the symptoms to be more helpful.