I have fussed with the derailluer for the past our. It appears that one of the brackets is bent. To top it off the little plastic spoke guard has parted company from the derailleur mount. I found my derailleur was actually contacting the spokes on my wheel it was so badly bent. It then would hunt from gear to gear no matter what I did. So now if it is not perfectly adjusted, the chain when going into first gear hops over the backside of the last sprocket and into the spokes.
It is getting to be pretty frustrating. I may just give up fighting with it and drop in a internal hub. I could probably send it back to Yan as well and get them to fix it. Sort of a bummer though getting a new bike and have this sort of issue. There was no external damage to the box but the derailleur bracket is obviously bent if it is contacting the spokes.
I don't want to over stress it and snap it off bending it back either. The problem now is the little spokeguard just spins and rattles as the wheel rotates. That one would be a real PITA to change too I am betting. Hard to get a good feel for the bike when you can't select a gear without it hopping to another one. It makes it easy to almost fall on your face.
I have another one in the box that maybe I'll pull out tomorrow. I will see if it has the same issue. It has a lot of promise. If the average person got one like I did the'd be sending it back for sure. I can't see doing that if I can resolve the problem myself but then again I don't want to spend a bunch of time when it should have worked out of the box.