heating issue would be from sitting and idling for a extended period of time like in a traffic jam and not from on the highway as air is flowing fast over the cooling fins of the cylinder and cooling it much better at speeds rather than sitting in traffic.
how often is the oil changed?
That is good every 2500 miles. you can never change oil to much. do you use Mobil 1 motorcycle oil or the car oil?
glad to help and you have a Merry Christmas and a Happy New Year also