i work at a local bike shop and we recently had a '02 R1 in that had no power and fell flat on its face all up n down the rpm range...come to find out the servo motor was bad for the exhaust valve and when it was replace the thing ran properly again...so how can removing the exhaust valve completely help ur bike run better...??

 

Because the valve is closed thereby restricting airflow until you kick it in the ****. Then the servo opens the butterfly and the exhaust flows unrestricted. Stick a banana in your cars tail pipe and let us know how it runs[8D]

 

i have a california model 02 954rr and i was wondering if they had it on the 49 state bikes and would it be better if it was taken off and would it make the bikes power band smoother and would the bike run correctly with it taken off im trying to see if i take it off would it make my bikes power band smoother

 

An aftermarket pipe gets rid of the valve -- the servo has to stay unless someone's figured out how to make the ECU think it's still there. You'll get error codes on the FI if you remove the servo.

 

yeah i understand the concept of the valve...when we were trying to determine if it was the servo we rode it with the valves tied open...it still did not run great...it was better than with the falty servo...but it was still not as good as when we installed the new servo...i've had many bikes and i do know and understand the idea of the unrestricted airflow concept...but why have the manufactures gone to computer controlled valves for back pressure...on another note whats up with FMF's "powerbomb" header design on their new 4stroke dirtbike pipes...they look like they have a miniture expansion chamber like 2stroke pipes...anyway i'm just wondering how it all relates into backpressure and how going to unrestricted improves

 

I don't know about the 4 stroke dirt bikes -- just that they're a lot peppier than they used to be. As far as the R1 with the faulty servo -- only thing I can think of is maybe the ECU knew it was bad so it wasn't sending enough gas. The valve, in theory, will give the bike slightly more torque at low RPM's in stock trim. However adding only a slip on will produce better results. My personal opinion (gathered from peeps smarter than me) is that it's more of an EPA thing than a performance enhancer. I guarantee you the superbikes aren't running it.