I bought this 2009 Roadliner brand new and now have 300 miles on it. On warmup while Idling the engine, there is a lot of engine noise - heavy clattering - rapping - nocking which seems to quiet down a bit by increasing the RPM. I am running the highest octane Sunoco in it. Last night I added 3 gallons of Shell 93 octane and stopped for 1 hour. When I started the bike backup the engine noise was much louder then it has ever sounded. It seemed to quiet some as I increased the RPM up to 2000 RPM. ???