Consistent temps over 400 will warp the head but normally that isn't an issue with the LO 206.
There is no advantage to running this engine that hot.
The rules are such that it's hard to do anything to affect the engine temp.
Ambient temp is the biggest influence on engine temp. Driver size (weight) is another. How much grip you have and how long the kart is locked down to the track in the corners.
Asphalt, sticky tires, high ambient temp, heavy drivers and tight kart will equal high engine temps as opposed to the opposite conditions.
Keep in mind that you are not allowed to tape up the blower housing, change jets, change timing etc.