1981 XS650 Special 2

These are not highly tuned motors. They have roller or ball bearings throughout that need just a little oil and that oil can be hot. These bearings do not have a lot of sliding/friction building action. In slow speed you are not developing a lot of hp/temp. I don't remember posts worrying about overheating here. If you are concerned, change the oil.
In olden days we used a solvent soap, and sprayed down onto a warm engine, let it soak, and then washed it off with the water hose... and a very satisfying wispy smoke with an exquisite odor arose. If I remember the name I'll see if I can buy some...but you know, commiecaliandrules, so to say.

I don't think I was clear. When the wind blows over us we do not much feel the heat of the motor. When the wind does not blow over us, we do feel the heat of the motor. This is Zen :)