The belt is new, and it is a Yamaha stock belt. The vibration started at 700 miles and seems to be getting worse, by the end of the day your hands are numb. Been to the dealer several times, and they say there is nothing wrong. Could after market dampers be used if Yamaha won't sell these in a kit? I'm looking forward on a good upcoming season, but not on this sled the way it is. And when I called Yamaha, they did not offer any help at all. I was told to sell it.
There is definitely something wrong, the three cylinder engine is very smooth. If your dealer told you to sell the sled then it's time for a new dealer.