Prepare the BBQ as follows:
1. Underneath the grill on top of the coals, lava rocks or tile place a metal cake pan that is larger than the roast and fill approximately 2/3 full of water. This will stop any flaring of the roast and drippings and also prevents the roast from any drying out.
2. Start BBQ only on the OPPOSITE side from where you are cooking the roast. Start on HIGH heat and after searing the roast, turn heat down to LOW to MEDIUM.
3. During cooking, set the roast on end and turn 1/4 turn EVERY 15 MINUTES, doing the ends of the roast last. Generally, cooking time is 1/2 hour per pound.
4. It is preferable to use a meat thermometer to determine how well done you like the meat.

Recipe from the Bison Producers of Alberta Canada

2 1/4 lbs. leftover buffalo roast cut in strips 1/2″ thick
1/3 cup flour
1 tsp. salt
1/2 cup finely chopped onion
1 1/2 cups mushrooms cut in quarters or small pieces
1 clove garlic, finely chopped
2 T. butter
6 T. salad oil (divided)
1 cup beef broth
2 T. Worcestershire sauce
1 cup sour cream
Buttered rice or noodles
Chopped parsley

Directions 

Dust meat strips in a bag with flour and salt. Sauté onion, mushrooms and garlic in 2 tbsp. each of butter and oil in a large frying pan. Remove vegetables from pan.

Add remaining oil to pan; brown meat quickly in heated oil, then remove from pan. Combine remaining flour mixture with drippings. Stir in broth and Worcestershire sauce; cook until thickened. Blend in sour cream and heat slowly.

Add meat and vegetables and heat, but do not boil. Serve over rice or noodles, sprinkle with parsley. Yields 4 -5 servings.