You don't win 28 AMA championships and over 200 race wins by riding a stock motorcycle with over the counter parts. You win it by customizing your bike to get the best performance possible. The professional technicians at Pro Circuit have built a winning dynasty through innovation and dedication. Riders of most 2 and 4 stroke engines can experience increased performance with Pro Circuits race tested engine head modification.
You Tube Video Link: http://www.youtube.com/watch?v=5BfVF0wPli4