sorry to bring this up, but there are a few relevant posts on the pk80 ring size thing making it less than a 70cc:Are they really 80cc motors? This is a first for me. I have never seen an 80cc bicycle engine kit out of Asia. Not yet..Until now that is.. Does anyone know the bore and stroke of these? If they are 80cc. This is a first... Does anyone have any Info on these? 80cc ? Really? Let me know..thanks..And..Enjoy the ride..