Drain pineapple juice into a small bowl. Add teriyaki sauce and mix.
Place pineapple slices and 3 tablespoons of the pineapple teriyaki mixture into a re-sealable plastic bag. Turn to coat and set aside.
Shape hamburger into 4 patties and spoon remaining pineapple teriyaki sauce over top.
Preheat grill to medium high heat.  Place burger patties on hot grill for about 6 minutes a side or until desired doneness.
Place buttered buns on grill, cut side down to toast lightly.
Remove pineapple slices from bag and place on grill and cook until slightly browned and warmed through.
Assemble burgers with patty, pineapple slices, lettuce, onion slices, Swiss cheese and bacon.
Enjoy!
Yield: 4 1/4 lb. burgers