I saw this on a cookin show a while back and now this is literally the only way i make my yams. First cut them up into fairly thick slices then brush olive oil onto both sides put them onto your bbq and squirt on salad dressing, i use roasted tomatoe and basil dressing and they turn out AWESOME. I don't have an exact cook time but they should REALLY have the black grill marks singed into them. These really get that nice smoked taste, they taste sooooooooooooo good.