Preheat oven to 375ºF; line a rimmed baking sheet with parchment paper. Lay bacon on sheet and brush both sides with 2 Tbsp. maple syrup. Bake, turning once, until crisp and browned, 20 to 25 minutes. Discard fat; lower oven temperature to 200ºF. Coarsely chop bacon.
In a large bowl, mix flour, baking powder, baking soda and salt. In a bowl, whisk buttermilk with 2 Tbsp. canola oil, eggs and remaining maple syrup. Stir buttermilk mixture into flour mixture. Fold in bacon.
Preheat a 7-inch waffle iron. Brush with a bit of oil and add 1/2 cup batter. Cook until lightly browned and crisp, 6 minutes. Place waffle on a plate in oven; cook remaining waffles. Serve with additional maple syrup, if desired.