1983 Honda gl1100 overheating issue?

My 1983 Honda gl1100 overheats when riding but cools down at a stop it has a new thermostat and brand new 50/50 coolant my water pump is working just fine could it just be the temp sensor? It reads fine some days and most of the other days it runs hot like red line hot

Try removing & back flushing the radiator - while it is out do an internal inspection of all the hoses for partial collapse of the lining.
While you're at it remove the temperature sensor & rig it up in a pot of water with a thermometer over a hike stove. You'll need to connect it's body to the bikes frame electrically too as well as the central terminal. As you raise the temperature see what the gauge reads. Check specs for the bike & then you'll know whether or not there's a problem with the bike or the gauge or sensor