I looked at my CPV3 again and you're right there isn't one. For some reason I thought I took mine off when I crashed and did a rebuild but I guess I didn't.

It's probably pressed on like the tail rotor. If your new BL motor has a flat spot on the shaft to accept a grub screw style pinion I wouldn't worry about getting the stock pinion off and re using it. I think the gears on the CPV3 are 48 pitch, so you'd need to find what the new motor shaft diameter is in mm's and then get a pinion that will fit.