where to find replacement motor mount bolts.

6mm 1.0 with the assumption that you got a crappy Chinese 48 cc / 66 cc / "80" 2 stroke?

I got my stud kit from SickBikeParts.com and am very happy with it. They have a kit that covers all the motor studs except the head studs, since they are different size on different motors the head studs are sold separately. They gave me great service, fast shipping and everything I have ever gotten from them was a quality product at a good price.....

You can also get M6mm boltsd at auto parts stores and cut off the top of the bolt- you can get really long ones that way- that's what I've done to mount a couple of motors before the oversized mount on the motors came out-

I filed the old narrow mounts wider, and then using extra long bolt/studs, wrapped them around the frame- works well, but slight pinch on frame tubes- glad there's the wide mount now..