I got a 140xr, the cam timing was advanced out of the box so who knows what damage that may have done to the valves, the engine mount and frame bolts are mostly threaded and seized they didn't even get the nuts on all the way before they seized, the throttle broke after a couple rides, there's gaps and holes in the frame that hold water and rust drizzles from them all over the bike, the fuel tank was full of plastic shards(I hear this common for chingas), the flywheel inner thread is threaded so a flywheel puller won't work, there's more but I just can't remember.
I don't think it's a problem with this model cuz other people have them and think they're great, it's just the bike I got was dodgy, it's almost like they've done it on purpose it's that bad or maybe the china man who assembled it was drunk or something