If you recently drained and re-filled coolant, you may need to BURP the system.
Remove radiator cap. Idle engine until coolant circulates. Circulate for a while, allowing air pockets in cooling system time to exit through the open radiator fill nozzle. Shut 'er down; top off radiator; fill reservoir to "FULL" mark. You have now burped your cooling system. Replace radiator cap and ride on!
Air pockets can occlude coolant circulation, causing the symptoms you mention.
Hope the technique works; if not--procedure easily performed; you're no worse off than when you started!
“You better put down that gun. You got two ways to go, put it down or use it. Even if you tie me, you’re gonna be dead.” "John Russell" (Paul Newman), Hombre