For the last two decades bikes have been equipped with an exhaust flap valve (also called as EXUP valve) to improve low down torque with the hindering of the flow of escaping gasses creating back pressure in the exhaust system. As the revs rise and the more you open the throttle, this valve opens more and more so the gasses can leave unblocked. This valve and its housing is welded after the header’s downpipes right before the collector pipe and/or the collector chamber/catalytic converter so removing this alone from the factory system is not worth the time, the money and the effort itself since the OEM system in the most cases is still low quality and heavy as hell. Of course, titanium OEM systems exist but finding an exhaust shop with titanium welding capabilities isn’t easy and will cost you an arm and a leg in labour to remove the exhaust valve from the system. So it’s easier and gives much better result to opt for an aftermarket end-can or whole system. Either way you take, you will need an Exhaust Servo Eliminator to complete the job properly!