one of my yorkies use to do that but she also use to have pains in her tummy which would make a grumbleing sound.it turned out she had a tummy ulcer and ibs,after treatment she was fine.the yorkies i have now are sick now and again and i have noticed that if i feed them in the morning as soon as i get up then a snack in the afternoon then feed them not long before we go to bed they dont do it, maybe your yorkie has a lot of acid in its tum and it gets rid of the food quick so by the time morning comes the tummys empty and it brings up bile,which a dog only does when the tums empty,try that and see if it helps
