If it stops with the dial down, only one area to look in. On the yuki I have noticed that the ears of the balance bridge get bent very easily. I'm guessing you cked the hair spring to make sure everything is ok there. If so, here is my guess. Like lumbee said, could be a cracked or missing jewel in the base plate for the end of the balance staff that sits there. Could need some oil, although that doesn't usually cause your problem. Have you tried loosening the 2 screws that hold the bridge on and see if it starts on it's own. If so, slightly bend the ears down and gradually tighten the bride screws. I'm just guessing on all this stuff. Here is the order I think it should be cked in. First remove the bridge assy. Then ck the balance staff. Make sure it's straight and not broken off. Then look at the jewel, if it has one, in the base plate to make sure it's not cracked or cocked or missing. You will need a loop to ck it. If all that looks good, simply install the balance bridge and only start the 2 screws. It should kick off as soon as you push the stem in. If not, rotate back and forth gently to see if it starts. If it does, turn each screw 1 flat at time. If it stops after 2 0r 3 turns, your bride is bent. If it won't run at all, you now have to go to the train bridge. That's a whole new set of problems.