Exhaust Butterfly Valve

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dan_h2sx
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Exhaust Butterfly Valve

Post by dan_h2sx » Fri Jan 10, 2020 12:18 pm


As I'm located in germany and we have very strict laws regarding aftermarket exhaust system, the only compliant muffler for me is the akra.
I was wondering what would happen if I just loosend the exhaust valve cables on the muffler side.
Would the bike go to limp mode? Or would it just run as normal?
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Re: Exhaust Butterfly Valve

Post by vcyclenut » Fri Jan 10, 2020 12:46 pm


There is nothing to gain by disabling the exhaust valve, just leave it be

but to answer your question , you can just remove the cables and leave the servo motor that is under the seat plugged in and you will not get a check engine light.

if you did get a check engine light for unplugging it the bike would not go into limp mode, you just wont be able to switch modes till you clear it
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dan_h2sx
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Re: Exhaust Butterfly Valve

Post by dan_h2sx » Fri Jan 10, 2020 1:23 pm


vcyclenut wrote:
Fri Jan 10, 2020 12:46 pm
There is nothing to gain by disabling the exhaust valve, just leave it be

Won't the bike be a little louder then? That is my primary goal bc of the strict exhaust regulations we have here.

Do you know at what rpm the valve regularly opens?

Thanks for your answer btw :D
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Re: Exhaust Butterfly Valve

Post by vcyclenut » Fri Jan 10, 2020 1:30 pm


dan_h2sx wrote:
Fri Jan 10, 2020 1:23 pm
vcyclenut wrote:
Fri Jan 10, 2020 12:46 pm
There is nothing to gain by disabling the exhaust valve, just leave it be

Won't the bike be a little louder then? That is my primary goal bc of the strict exhaust regulations we have here.

Do you know at what rpm the valve regularly opens?

Thanks for your answer btw :D
I didn't look at it from that perspective. you would have to test that but if it is it would be minimal,

its open most of the time, im not sure exactly when it closes down as its not listed in the flash soft ware, I know its open at idle and its open at full throttle the entire time
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dan_h2sx
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Re: Exhaust Butterfly Valve

Post by dan_h2sx » Fri Jan 10, 2020 1:36 pm


vcyclenut wrote:
Fri Jan 10, 2020 12:46 pm

I didn't look at it from that perspective. you would have to test that but if it is it would be minimal,

its open most of the time, im not sure exactly when it closes down as its not listed in the flash soft ware, I know its open at idle and its open at full throttle the entire time
With this information, I might leave it alone entirely. It's just not worth the hassle if I don't know if it really improves the sound.

Thanks again anyway, mate! :)
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Re: Exhaust Butterfly Valve

Post by Vex » Fri Jan 10, 2020 5:49 pm


vcyclenut wrote:
Fri Jan 10, 2020 12:46 pm
if you did get a check engine light for unplugging it the bike would not go into limp mode, you just wont be able to switch modes till you clear it
Does your tune deal with that? Someone was mentioning if you do a full exhaust swap you could remove the servo motor as it wasn't needed. Freed up some under seat space as well, which I wouldn't mind.
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Re: Exhaust Butterfly Valve

Post by vcyclenut » Fri Jan 10, 2020 5:52 pm


Vex wrote:
Fri Jan 10, 2020 5:49 pm
vcyclenut wrote:
Fri Jan 10, 2020 12:46 pm
if you did get a check engine light for unplugging it the bike would not go into limp mode, you just wont be able to switch modes till you clear it
Does your tune deal with that? Someone was mentioning if you do a full exhaust swap you could remove the servo motor as it wasn't needed. Freed up some under seat space as well, which I wouldn't mind.

Yes I disable it so you don’t get a code when unplugged on full exhaust flashes.

I leave it active unless asked not to on slip on or stock pipe flashes.
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Re: Exhaust Butterfly Valve

Post by Racer-X » Fri Jan 10, 2020 11:36 pm


@vcyclenut in this video about the ZX-10 it shows that the valve is closed for a part of the rev range to minimise noise. Is this not the case on the H2SX?

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Fast5ru
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Re: Exhaust Butterfly Valve

Post by Fast5ru » Sun Jan 12, 2020 2:02 pm


Hello from Russia,
I have done removal of db killers:



You need to drill out rivets, take off carbon fiber end, brake out weld traces that holds baffles in place , take them out, put in carbon fiber end cap and rivet it in back.

Result would be more deep expensive bass sound.
Enjoy it.
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Re: Exhaust Butterfly Valve

Post by vcyclenut » Mon Jan 13, 2020 1:31 pm


Racer-X wrote:
Fri Jan 10, 2020 11:36 pm
@vcyclenut in this video about the ZX-10 it shows that the valve is closed for a part of the rev range to minimise noise. Is this not the case on the H2SX?

as I answered

its open most of the time, im not sure exactly when it closes down as its not listed in the flash soft ware, I know its open at idle and its open at full throttle the entire time

I also can say I did not feel any difference riding the bike with the stock exhaust with it disconnected vs it left alone

I tested it on the dyno connected vs disconnected the runs were identical
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