My ATV isn't starting - what is it?

[Grave85]

I am new to this site need help just replaced my starter on my 125 four wheeler and it starts but I hear a lot of noise but not from the starter it’s like cracking , grinding kicking out . It was doing that at first thinking it was the starter so we replaced it . Benched tested it and it was bad. But I still have a lot of noise when starting it up. It runs. But when starting it sounds bad. Any help it’s a china one. For my boy.