plus 2 teeth on the rear has the right amount of naughtiness , Changing the front sprocket can alter speedo/mileage readings? (not a problem on a track bike) @Moon Sorry photo removed after posting this earlier ,don't want to be a silly billy http://1000rr.co.uk/threads/silly-billy-anyone-from-on-here.27253/#post-386553
Changing either sprocket will alter the speedo readings as your wheel is now rotating at a different speed to what the bike thinks it is. Going +2 on the rear is 4.5% difference on top of the already 5% out speedo, so your about 9.5% out. If you fit a 55 profile rear tyre it will lower the % slightly, either that or fit a speedo healer (or just leave it) Nice pic