Hello cc Welcome to the forum glad you joined us

I have never bought off E-Bay, I've heard good things and bad things.

I'm not sure what bike you plan on using but if get lucky you may not have a problem mounting the motor.

I drilled my frame but I will NOT recommend anybody do that.

I had a bunch of links for solving that problem so you would not have to drill the frame. But I had PC problems and lost all my links.

Here is some links.......http://motorbicycling.com/f6/oversiz...olved-171.html

Modify the mounts or the frame

I believe boy go fast has a mount for sell that will solve that problem...it should be in one of those links