I took my 2018 Eldorado in for the 6000 mile service. After getting the bike back it runs a lot "rougher" below 4500 RPM. Before anything above 2000 RPM was smooth as butter. At first I thought it was just mental on my part but my wife asked about it the first time I rode her after the service. Below 4000 it runs like a tractor. Any ideas before I go interrogate the dealer?