the OLD pipe for the kt & ARC in sportsman class in QLD

Hello fellow karters  and to the folks that started after these motors when  at there prime they where the AKA motor e.g early 2000  the kt100 & the ARC. yes times have past and motors that are  new have become quicker. with a new motor now in the late 2000   comes with a axust  that is tuned for that motor so MY question is why do / dose the kt  or the arc has to run the old aka 39 muffler. I still go and race but these new motors with there you bute pipes will always run one two three  Maybe its time to bring back the power Mack  pipe all kt arc run them in the day cheers