Place 4 peeled and diced sweetpotatoes in the bottom of a crockpot.
Place pork roast on top of the sweetpotatoes.
In a bowl, add ½ cup packed brown sugar, ¼ teaspoon cayenne pepper, ¼ teaspoon black pepper, ¼ teaspoon garlic powder, and ½ teaspoon onion powder. Mix well.
Sprinkle mixture over top of the roast. Cover and cook on low for 8 to 10 hours.
Remove pork and slice. Spoon juices over pork and potatoes.