I'm not sure I know what you mean... But the all the exhaust valve does is act as a sound supressor, to make it db legal. If you bypass it is allows the engine to breathe as engineered to do. Putting on a slipon and not having the "fi fix" will not do anything but annoy you, because you will have your "FI" light ont. Your bike will run fine even with the light on....

 

The valve actually helps keep the compression up so you have power in the low and mid power band. It is partially closed while in the low and mid range to keep the engine compression up. When you are in the top end of the power band, it is open.

Some people learn this only after they have removed the valve and installed say a full system exhaust and think they are getting more power and they do but only on the top end. They end up loosing on the low to mid. Sprocket change is necessary to compensate for the lost power.

I am not sure about the sound thing but I am sure it is more quite with the valve installed.

 

I did the jumper mod and there was a huge difference in the upper rev range. Prior t the mod the power would taper off towards the top, but after the mod it kept charging all the way to the limiter! I experienced no problems with it. I've got a Yosh on now so doesn't matter.