If I am wrong, then my appologies, but the way I read this in the past was that the valve closed some at higher RPM's in order to regulate the total db rating of the exhaust. That being said, it would not affect an aftermarket pipe, BUT, if it also, in fact, controls fuel, then yes, it would obviously assist with any pipe. I have seen nothing that proves this theory though.

I have a new pipe that I just got in yesterday and it will be interesting to see the difference on the dyno with and without the jumper in place.

What I would like to know is if there is any way to get rid of the whole damned flapper valve motor altogether. If I ain't using it, I don't want the extra weight in there. Any clues on that one?

 

I saw the dyno runs on a bike that had an aftermarket exhaust and with & without the jumper mod. It made a difference of 5+ HP. The electronic engineers and programmers at Kawasaki wouldn't allow the ECu to dump extra raw fuel in the engine with the valve partially closed. That would definitely fail the EPA Emmissions test even if it passed the DB test. So with the valve partially closed and fuel cut off, it passes both the tests. Smart guys those Kawasaki Engineers and smarter yet to just jump the ECU and disable the restriction!

 

meanstrk, IVANS makes a servo eliminator. You take that whole crappy servo box out of there all together and just plug in the SUPER SMALL eliminator into the stock harness. Very simple. 5 Minutes. $100 bucks. very easy.

 

By the way Blackninja, the jumper mod gave me 6 hp. I work at a performance shop with free access to the dyno. Definately worth it.