Sorry, one more thing. I realized I've never had a spring on my moped (cuz I'm told the spring is external, and I don't see one, I'll attach a picture later). And the loud harley noise also stops when I plug up a hole in the left underside of the cylinder head. It seems like the hole is supposed to be there, but I don't know if it is supposed to be plugged with something, like a screw. Thanks again for your help.