So I recently bought a Yeah3 and a 10 ball. I used the stock bearing for about 5 minutes and then went on to replace the bearing with the 10 ball. While doing so, I realized that the bearing alignment with the bearing seat was very tight. I used the 10 ball with the Yeah3 for about 30 minutes until my Yeah3 suddenly became responsive.
I then decided to try and remove the 10 ball, which I managed to do with A LOT of effort, and promptly put back in the stock bearing. I’ve read around that the C3 bearing seats are exceptionally tight, so my dad came up with the idea of taking fine sandpaper and sanding the actual bearing seat itself in order to make it less tight. Is this a good idea? Or will it somehow ruin the yoyo by making the bearing seat too loose? Any feedback is appreciated.
And my other question is… when i first started to use the 10 ball, it was unusually quiet. It was almost silent. But after about 20 minutes of usage, it suddenly became loud. Is this common with 10 ball bearings? And does that mean i would have to break it in in order for it to become silent again?
Thanks again 
The argument against sanding the seat is it WILL change things a little bit and COULD affect the performance of the yoyo as a whole and could increase vibe. Companies such as YYF recommend against doing what you’re suggesting you’re going to do for the above reasons. In fact, it was recently said. However, YYJ bearing seats are loose and those are still amazing yoyos even though the bearing falls right out when opened.
My thoughts: Do it very carefully and as little as possible. It should be tight. They meant it to be that way. I’m getting a DiBase soon, so I’m going to be dealing with this myself soon.
Now, the 10Ball:
Yes, they start off dead silent, then as they break in, they are horribly noisy. Keep playing them for a few more hours or days. It will eventually go silent again. If it bothers you, feel free to add a drop of VM4 oil to it and enjoy the silence while you keep on breaking that bearing. So, yeah, you’re right on.
I’d be worried about the bearing though if your Yeah went responsive. It could be a part of the fact that the bearing is breaking in that has something to do with it.
c3 yo-yos have very very tight bearing seats, i recently ruined my di base trying to remove a center-trac bearing from it. the thing about tight bearing seats is that when you go to replace the bearing, it grinds aluminum off of the bearing seat and that gets into the bearing which can slow the bearing down considerably.
Bearing seats on C3’ are reaaaaly tight.
I’ve can’t speak on the tight bearing seat but I can attest to the problems with the 10 ball. Mine was very snaggy and responsive. It always snagged back when exiting a gt for example. It went from silent to alittle noisy to LOUD to silent to loud every 10 or 20 throws then it just jammed up on me. It also varied between tightly seated and falling off. That being said, I’d recommend choosing another bearing to use as a constant in your c3 yoyo as you experiment with it. Not hating on the 10 ball, just think it’s not the best bearing to judge with.
I would just leave it be. As you open and close the yoyo, the side the bearing is not stuck on will become looser, replacing a bearing is not really needed, but with a bearing tool it will come out, and if you do that often enough it will also become looser. Sanding can cause problems but if you really want to take a yoyo and modify a specific design aspect, then go for it, but that tightness was no accident, keep that in mind.
OMG! I did the same thing toooo. And the same happened to me. Then i tried my yyf bearings on my Yeah3 but it was unresponsive… I think its the fact that the 10 ball bearing is a bit flatter than yyf bearing. I want a solution to this too, i brought my 10 ball just for my yeah 3 and it would be a waste if it makes Yeah3 responsive 
I found a temporary solution. I ended up putting back in the stock bearing, and putting the 10 ball in a my Irony. I used both of the yoyos for about a day and decided to try and switch back the bearings. The 10 ball fit in the Yeah3 a easier than last time, and is fully unresponsive. I think if you try this you should be able to utilize the 10 ball and the Yeah3 together.
But the reason why I called it a “temporary solution” is because the 10 ball is now unresponsive and works fine in my Yeah3, but the bearing is still very loud. I’m assuming that I still need to break in the yoyo… but its already been a week of constant usage… and from what I’ve read, the 10ball should take about a week to break in. Keep me posted on how this works for you. 
Sorry I wasn’t able to reply sooner, but my yeah3 is still responsive after all this time and it is still loud. I tried using a different string ( 422 chaos ) then it became unresponsive. How is yours doing?
Dont sand it, if it’s too tight to remove, put it in the freezer (no joke) for some time, maybe 10 minutes. Aluminum’s coefficient of thermal expansion is almost double that of steels, meaning that the aluminum will shrink more than the steel & the bearing will be easier to wiggle off.