Hello I have a bone stock 2021 low rider s and I love it. Has less than 2,000 miles on it and I have had one regular 1,000 mile service done to it. Ever since the service I have noticed a whistle/purging sound that is in tune with the firing pattern when on and off acceleration. Was not always there and have never heard this on another low rider. It is significant when cold starting “I live in Florida” so whatever cold means to some people 😂. And gets less significant as I ride and warm up. Almost sounds like a little turbo spooling as I accelerate. Don’t tell me to get loud pipes 😂. I understand Harley’s are loud but this seems like escaping air from head or valve area and not the exhaust. Comes from the front cylinder.