Grease 2 (9" x 5") loaf pans. In a large bowl, dissolve yeast and sugar in warm water. Let stand 5 to 10 minutes or until foamy. Add oil and sourdough starter. Add dry ingredients and mix. On a lightly floured board, knead lightly for about 2 minutes. Place into greased pans; let rise in a warm place until double in bulk, about 1-1/2 hours. Preheat oven to 325 F. Bake 20 minutes. Cover pans with foil; bake another 15 minutes or until loaf sounds hollow when trapped on bottom. Makes 2 loaves.