In deep woods and twisty trails where you are going slow and there is almost no air passing through the radiator, high temps are very possible. I have found that the PWR is really not much better than stock when you still have very little air flow. Between the 2, the Afco is probably a better cooler. As others have said, make sure you are not running lean on your carb. Aside from trying the Afco instead, your only other helpful options would be to run a coolant booster, such as Amsoil dominator coolant boost.