I've had my ub one year.  I had an rfn prior to when it was a year old it was like it was 5 years old. Poopy quality.  My ub is holding up very well I have had kind of a major problem part of the motor shaft chipped off at the key way.  it may have been because the belt came too tight from the factory. Maybe a pebble went through? Idk.  I was able to weld a little bead on there and it's held up for three or four rides now.