I purchased my '05 RT two years ago and have loved every minute of riding and servicing it. A few weeks ago during our bi-annual "love" bug infestation my average mpg dropped from 51.1 to 47. So I attributed it to a dirty air filter and cleaned and re-oiled the KN filter which was only slightly dirty.
Today I rode the bike again and the average mpg had dropped to 42.0. The bike presents as running well at idle, hard accelerations, and sustained 75-80 mph interstate distances.
I plan on purchasing a V-Max to see if the throttle bodies are calibrated. I don't see that this has been done since new even though it has been maintained by a BMW dealer since new until I purchased it. The bike has 38K on it and all service has been done per the manual. Valves are adjusted per specs and I have filled the tank with Shell 93 octane gas 4 times over the course of the drop in mpg.
What is puzzling is how the bike appears to run well but the dramatic drop in mpg occurred within in 3 weeks.
Does anyone out there have any suggestions as to what else I need to examine/consider?