Mine were 110cc honda50 clones. A hell of alot of of fun.
We rode them hard every weekend for 12 months until the swingarms and rear wheel spokes disintegrated. Mind you, I'm 300 lbs. I think they performed great for $100 each.
We never jumped them far, mostly pavement and more of a flat style dirt track.
I still have one engine in the garage. Neither skipped a beat in that 12 months. I want to put it in another creation at some point.
These bikes are fun, and usually so cheap you can throw them away if you need to. -BIG DAN