Re: Hello all, I could use some help
There's a reason that they have the saying "they don't make 'em like they used to." Definitely go with a vintage bike if the frame is in decent shape. Any steel-framed American-made bike is most likely going to be nice and sturdy.
If you're looking for a 4-stroke center mount, there are currently backordered just about everywhere. Look through some threads here, there are a few about these motors.