I was the chain snaped when I rode it. So I guess I'll need to realine the engine gear and back sprocket. And i'll se about filling that gap. I problem is those boltsI disagree - that gap in front where whole force of the motor is hitting the frame at just the two tips of the mount is very bad (I've seen that pressure spread the cases till compression is lost) - all that is needed is a chunk of metal or PVC that sits in the space so tips of motor mounts don't touch frame there.
Can't say much about the noise as that vid is too tiny - pics might help, but wondering if pedal chain is hitting motor.
Ouch..! File or dreml that mount opened or your frame might not live long. Those studs will snap.