Arrange turkey parts on a lightly greased grill 4 to 6 inches above a solid bed of low-glowing coals.
Wash yams, pat dry, rub with butter, pierce skin, and wrap in foil; place on grill beside turkey.
Cover barbecue and adjust dampers according to manufacturer's directions.
Cook for about 15 minutes or until turkey skin just becomes golden.
Turn turkey pieces over, cover, and continue cooking, turning pieces frequently to brown well on all sides, for 65 to 75 minutes longer or until meat near bone is no longer pink when slashed.
During last 20 minutes, brush turkey parts frequently with jelly baste.
Meanwhile, turn yams occasionally.
Every 1/2 hour add 5 or 6 briquets to fire, spacing them evenly, to maintain a constant temperature.
Remove turkey and yams to serving platter.
Offer condiments for yams.