Guys, guys, guys... I don't know what you are talking about. Admittedly I have been running 2 strokes for many decades. I used to curse 2 strokes until I learned what they needed. Yes, the China Girl is cheaply made, even the bearings in it, but isn't pricepoint what the customer is asking for?
But if it self destructs in 100 miles? Hey, I've taken 100 mile daily rides on mine, what's up with yours?
These motors are perfectly designed for what they are supposed to do: 25mph universal bicycle assist at the lowest cost.
This is why they sell so well.
Years ago I was into 4X4 off-roading. Most of us bought an old truck or SUV and put $$$ in to rebuild it. I had a buddy buy a brand new Lada Niva. It was cheaper new than our old 4x4 trucks used. He brought it home, ignored the warrantee, and completely dismantled it. New SKF bearings and seals, Painted and undercoated the inner fenders, and many other fine touches let this Niva run trouble free for many years. Doing this to a China girl could not hurt.