Does your state have a Lemon Law? I guess I would go back to the dealer, and beg for help, talk with your salesman, talk with the store owner, and tell them this is unacceptable, and tell them you intend to do what you need to do, within the law to get this issue solved. You can show the video, and tell them that you have a friend (me that intends to call local and statewide radio programs about the issue you have. In the state of Wisconsin the purchase of Yamaha ATVs are on hold until this problem is researched further. I actually got a thank you for the heads up on this issue, I did show the video, and reiterated that Yamaha has indicated that this issue is within tolerance, but most don't do it, but when it does they wont fix it. You get me the name of your dealer, and any radio talk program (sports or open line discussion) and I will try to get in and tell your story. I will be nice and respectful, but clear that this is unacceptable. Also get me the name of a major Tennessee outdoor sporting event, there should be a way to make Yamaha take notice. I purchased an extended warranty, I am not sure it is any good.
I see there is a major dealer that sells three different machines, if that is your dealer, they do have online reviews, you might be able to post one, I don't know if it would stay up, but a threat of a review might be helpful. Try to post a reference to you Youtube video! Remember be nice at first, you need them to feel sympathy for you, if they sense hostility at this point, they might stick to the no service approach. There will be time for aggressive response later, my suggestions are after you beg to get the machine you bought in the first place, a Yamaha that works properly!
Here is something I found on the internet
The Tennessee Lemon Law covers drivers whose vehicles suffer a nonconformity or defect within the first year of ownership or during the express warranty period (whichever comes first) that can't be repaired after repeated attempts (normally four) by a manufacturer-authorized dealership.