Welcome to the site !!
This is normal , first , the bikes are lean from the factory , use the jetting guide below to jet it correctly for your elevation , also , ALL , modern 4 strokes are extremely hot at the header (about 1500 degrees , so DO NOT touch the header , it will literally melt your skin) , so if they idle or run without air flowing thru the radiators they will overheat in no time , especially when stock jetting is in place
Rejetting will help as would adding a cooling fan (they sell fan kits for them here , in the link i provided below the Jetting Guide) will help if you ride in tight trails or any street use , or just putt around a lot , but neither will eliminate the glow , nor it overheating to some degree , your best bet is to not let it idle for more than 1 minute without airflow (basically moving/riding) , but the exhaust will always be extremely hot , if you fire your bike up at night , it will astound you as to how red the header actually gets ..... Stock jetting will most likely be around a 42 Pilot and a 142 Main Jet , which is way too lean , but needed to pass emissions so the bike can be sold , so you will be replacing the Pilot and Main jets with what is recommended on the list below ....... hope that helped some
Jetting Guide for Main Jet:(pilot 45) CRF450R/X
Sea level....165
2000 ft.......162
4000 ft.......160
6000 ft.......158
8000 ft.......155
Temperature/Elevation:
One main jet size (up/down) for every 2,000 feet or 25 degrees in temp.
Fan Kit :
https://www.crfsonly.com/catalog/produc ... ts_id/5360