It looks like there is some binding in the drive train. If you're on the stand and you give it a tiny bit of gas, your wheel should spin. In fact, it should spin a little bit at idle. Unless your wheel is touching the ground? I couldn't tell.
Jetting may be off. I've seen that setup with jetting as low as 58, and as high as 65. No power when running seems like a lean condition. I'd suggest you try up jetting just to see what you get.
Your electrical is fine, I think. Running reliably as it did with a good idle and no backfires, if it were me, I'd rule that out for now.