In a flap??

[Pork]

The 2010 GS has an exhaust valve to generate 'a more muscular sound' to quote BMW. This flap closes at noise testing revs and presumably stays open the rest of the time. From what I've read it is not an exhaust tuning valve like exup

Previous version don't have this flap

So to get a more muscular sound by adding sound reduction seems counter intuiative

The only logical explanation I can see is that the 2010 exhaust can is less noise restrictive than before, which opens up some options whilst looking stock

Or have I got it arsey-facey?

 

[Dainese Brave]

The valvue on the 2010 bike is there to close at the revs where the emissions are tested, and then open again when passed that point..

..Basically it is a method to get past the test, without having to restrict the performance of the engine as a whole.

I'm not sure if the new model was designed to have a 'throatier' exhaust note?...or if it is just a bi-product of the new engine? ...but noisier it most definately is.....and not to everyones taste, as I statedin an earlier thread I have started.

 

[Toad]

The valvue on the 2010 bike is there to close at the revs where the emissions are tested, and then open again when passed that point..

..Basically it is a method to get past the test, without having to restrict the performance of the engine as a whole.

I'm not sure if the new model was designed to have a 'throatier' exhaust note?...or if it is just a bi-product of the new engine? ...but noisier it most definately is.....and not to everyones taste, as I statedin an earlier thread I have started.

Hmmmm


I'd like to put the 2010 noise against my 08 bike with an Acro can and no baffles

 

[Deleted account 190920001]

yes it will have a less restrictive can but the valve also causes back pressure at lower revs meaning more of the fuel air stays in the cylinder to go bang. The result being better low end power.

 

[(RIP) Miff]

I thought of an idea similar to this YEARS ago (Honest, I DID).

I just wish I'd patented it

 

[Mr K]

2004 bikes had a valve too...

 

[Deleted account 190920001]

my 1990 Yamaha FZR1000R exup started it all so you would have had to go back a fair bit.

 

[wadham]

Hmmmm


I'd like to put the 2010 noise against my 08 bike with an Acro can and no baffles

Where shall we meet to compare Akro's.