So my wife and I just picked up this brand new 2021 125cc for my daughter and we noticed it has an odd rumbling/vibration issue when you hit high rpm.

I've already done an oil change on it and we run 91 octane gas in it. It's got roughly 4 hours of use on it. Can anyone explain or know what this issue would be?

https://youtu.be/u6sTgrxwQ0s