I believe my Roadster is off even more than yours. I used TuneECU last night to put a new fuel map on the bike, and set my speedo correction at -6%. I would prefer the speedo to be closer to actual and that should also keep the odo more accurate, rather than rolling on more miles. If your speedo is off by 6%, then for every 1000 miles you really put on the bike, the odo would be showing 1060 (thus showing higher miles on the bike than what has actually been covered).
Which menu allows you to bring the idle speed up a little? I did not see an obvious place to raise it. Thanks.