Welcome New Guy ... There are plenty of threads on this topic. If you decrease the rear sprocket teeth count by 8%, or what ever % of error, the speedo will be corrected. Most people wants lower gear but a few of us wants a higher gear for a more relax ride when doing long distance at high speed. Engine vibration and noise for long hours at high rev drains the mental energy. That little bit of more relax cruising may extend the long day a little bit more. It may also put the engine speed at the peak torque and HP when cruising at the high speed. Riding across the roads out west, Mojave, for example, you'll be going at 90-100 mph for extended time. RPM is high at that speed.