Re: neigbors call the cops!
Do yourself and the hobby a favor and muffle the engine. Running with open exhaust is an invitation to unwanted and negative attention that apparently you don't need and it reflects bad on the hobby of motorized bicycles.
Continue to ride as you are and I can guarantee that you'll see that police officer again and he won't be in any better mood than the first time. Be prepared.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"