Preheat oven to 350 F/ 175 C. Butter and lightly flour a 10c bundt cake form.
In a dry mixing bowl mix the flour, baking soda, baking powder, cocoa powder and coconut. If you can't find fine coconut, whirl regular dessicated coconut in a spice grinder briefly, being careful not to turn it into coconut paste. Measure out the 1/4 c called for after processing.
Peel and chop bananas and pulse in a blender along with the yogurt.
In a large mixing bowl cream the coconut oil and sugar. Add eggs,one at a time and mix well. Add banana mixture and coconut extract Add the mixed dry ingredients in three batches, alternating with milk. Pour the batter in the prepared pan. Place in the preheated oven and bake for about 50- 55 minutes, maintaining a steady temperature throughout, until a toothpick inserted along the central perimeter comes out clean. Cool in pan for about 10 minute and invert on a wire rack to finish cooling completely before slicing. Finish with a chocolate glaze if you wish.