I recently go a go big for 4a. I lost the bearing inside it, so I replaced it with a size c bearing, but sometimes the c bearing doesn’t want to spin. I’m pretty sure the go big had a size c in it.
First, the Go Big uses a half-width bearing, so you already have wrong bearing in there. So, I’m willing to bet binds aren’t working well for you. Second, how is the bearing you chose to use spinning outside the yoyo. I haven’t tried a SPEC bearing in my Go big because it’s not the right bearing to put in there. That bearing in my Go Big spins just fine.