In a large skillet, cook bacon until crisp; remove with a slotted spoon and set aside. Drain, reserving 3 tablespoons drippings. In the drippings, saute onion and green pepper until tender. Stir in flour, salt, mustard and pepper. Add soda and vinegar. Bring to a boil, stirring constantly; boil and stir for 1 minute. Gently stir in potatoes and bacon; heat through.