I have just upgraded the front sprocket on my 2001 to a 16 tooth item, also upgraded to the 12mm thick nut and new lock washer as it still had the old 9mm nut fitted, the vibration at 70 mph was driving me mad which is why I decided to change the sprocket. So now it revs at about 700 rpm lower, doesn't seem to have affected the performance by much if any, but now is super smooth up to almost 80 mph. Just thought I would put it out there chaps.