Remove the neck and giblets from chicken. Twist wing tips under the back. Cut one of the garlic cloves lengthwise in half. Rub skin of chicken with cut edge of garlic. Place garlic halves, lemon slices, and sweet pepper slices in cavity of chicken. Mince remaining two cloves of garlic. Combine minced garlic, basil, and salt; set aside. Starting at the neck on one side of the breast, slip your fingers between skin and meat, loosening the skin as you work toward the tail end. Once your entire hand is under the skin, free the skin around the thigh and leg area up to, but not around, the tip of the drumstick. Repeat on the other side of the breast. Rub garlic mixture over entire surface under skin. Securely fasten opening with water-soaked wooden toothpicks. Stir together oil and lemon juice; brush over chicken.
Arrange preheated coals around a drip pan in a covered grill. Test for medium heat above pan. Place chicken, breast side up, on grill over drip pan. Cover and grill for 1 to 1-1/4 hours or until chicken is no longer pink and the drumsticks move easily in their sockets, brushing occasionally with oil-lemon mixture. Remove chicken from grill and cover with foil. If desired, serve on a platter with steamed new potatoes and garnish with fresh oregano. Let stand for 5 minutes before carving. Makes 5 servings.