Re: 80cc? Is it really? And isn't 50cc a motorcycle?
You could get the bigger engine and, if questioned,give an honest but misleading answer:
"Officer, this is not a moped or motorcycle, but a 'motor assisted bicycle'. It's my understanding that these bikes, equipped with less than 50cc engines, are exempt from licensing/insurance requirements to which motorcycles are subject."
Heheheheh. This statement in no way asserts that YOUR engine is 50cc, and avoids the problem of lying to an officer, which would be a crime.