4G transmission out of round

I have a new kit that I have installed. Worked painstakingly to get the rag joint perfect and it is centered and doesn't wobble.

When I connected the chain to the 4G trans and spun the back tire, the rear wheel looks perfect but the 4G trans seems out of round and the belt is wobbling quite a bit.

Do I need to take the 4G all apart and reassemble or is it OK to wobble a bit.

My concern is that if it wobbles when I spin the tire by hand, what will happen when the engine is fired up and running.

Thanks for your feedback.

Box was is good condition when it arrived, so don't think the issue is there. It's definitely the rear pulley that is wobbling. It has the new free wheel so when you spin the rear tire as if you were just pedalling along, the engine chain turns, and the (I think it is called the jack drive) sprocket turns but then it free wheels and the belt going back to the engine does not move. What the belt does do is undulate because the jack drive shaft seems to be out of perfect round or out of center...

I haven't run the engine yet, I am just hand spin the rear wheel.

Any help on a fix or if this is normal would be appreciated.