Dude what do you expect??? You're riding a motorcycle in stop & go traffic that is wrapped completely in aerodynamic plastic, designed entirely under the premise that it would be in motion utilizing both low pressure & high pressure airflow simultaneously for proper cooling effect of not only the radiator, but the engine compartment as well...
You can change your glycol mixture or you can use something like Engine Ice to help as well, but those things only lower the running temps very slightly.
I suggest you install a switch so that you can manually turn the radiator fan on anytime you know you are going to be in some heavy traffic. All you have to do is run a wire from the ground side of the fan (same pole that the wire from the radiator runs to) then place a switch inline & ground to a part of the bike frame.
Just make sure you leave the radiator ground wiring in tact so that the rad switch will still work just like normal & kick on at 215 degrees.