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  #1  
Old 12-16-2007, 12:20 AM
 
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Default 07/08 600RR exhaust valve thingy?

So I got an 08 600RR last month. I've been riding a VFR for like 15years (not the same one) and the VFR is all I know. Then I get this CBR and WOW, its a kick in the pants. I love it. Then I started looking around the bike and I noticed this servo and cables under the tail that go to the exhaust pipe. It looks like some kind of valve for the exhaust. Anyone know what this thing is and what it does? Can/ should I disable it? Is it for smog and noise or for back pressure and torque? I have no idea. Can anyone enlighten me? Thanks.
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  #2  
Old 12-16-2007, 04:14 AM
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Default RE: 07/08 600RR exhaust valve thingy?

I don't believe any of the 600RR's have an exhaust valve.

Where exactly do you see the cables connected to the exhaust? I was intrigued by your question...........so I went down to the garage where my roommates 07 600RR lies (which is the same as the 08 models), and couldn't find any cables connected to the actual exhaust itself. The only wires I noticed are the ones that run right along the exhaust pipe to run the turnsignals/brake/plate lights. There was another one towards the base of the muffler that is connected to a black box and runs to behind the motor. But none of these cables/wires are actually "connected" to the exhaust.
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  #3  
Old 12-16-2007, 07:21 AM
 
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Default RE: 07/08 600RR exhaust valve thingy?

the exhaust valve in the 07 is before the cat just behind the oil pan

it is there for sound reduction

just like the 1000rr the cables can be removed with no adverse affect on performance.

some people will say that it will cause a decrease in low end torque because of reduced backpressure or some garbage like that but i posted a dyno sheet months ago showing cables before and after removal and the graphs were within 1hp of each other all the way through the curve

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  #4  
Old 12-16-2007, 08:32 AM
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Default RE: 07/08 600RR exhaust valve thingy?

^^ I stand corrected. I can't believe they have exhaust valves. I thought they only saved those for Ferrari's and Koenigsegg's. I'm going to have to start looking more closely.

.............my bike doesn't have it, does it?
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  #5  
Old 12-16-2007, 10:15 AM
 
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Default RE: 07/08 600RR exhaust valve thingy?

The only way to disable the exhaust valve is to disconnect the cables. I would only do this if you plan to replace the exhaust itself, otherwise it might make your performance worse. Don't remove the servo itself or the FI light will remain lit on your gauges. The only way to permanently remove the ex valve is to replace the ECU with the HRC model.
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  #6  
Old 12-16-2007, 10:32 AM
 
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Default RE: 07/08 600RR exhaust valve thingy?

it isn't there for sound reduction. it's there to vary the exhaust pressure under different rider demands. exhaust pressure is important. don't disable it.
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  #7  
Old 12-16-2007, 02:22 PM
 
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Default RE: 07/08 600RR exhaust valve thingy?

Quote:
ORIGINAL: knightslugger

it isn't there for sound reduction. it's there to vary the exhaust pressure under different rider demands. exhaust pressure is important. don't disable it.
i so beg to differ
it has been proven time and time again on a dyno that this has nothing to do with performance.

with my own 600rr on a dyno there was no difference on a dyno of a run with the cables on or off

this has also been proven over and over again on the 1000rr as well

here are some articles for the uninformed
http://www.uucmotorwerks.com/html_pr...torquemyth.htm

this site says that a good way to lose power is with backpressure
http://auto.howstuffworks.com/question172.htm

this site says you need the most exhaust velocity possible with backpressure as close as possible to zero
http://www.miata.net/garage/KnowYourCar/S4_Back.html

this one gives a formula that for every 1" hg of back pressure you have you lose 1hp
http://www.thrashercharged.com/tech_htm/exhaust.shtm

a little off topic but this site says exhaust valves are there to warm the cat on a cold engine
http://lotusesprit.com.au/docs/Exhau...re%20Valve.pdf

so many others but they all pretty much say the same thing.
in fact the only sites i found where they say that any backpressure is good is where the pipe is too large and allows the gas velocity to slow down, or just some guys opinion with no scientific evidence


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  #8  
Old 12-16-2007, 02:32 PM
f3racer
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Default RE: 07/08 600RR exhaust valve thingy?

ok wait i read somewhere that it was there to act as an alternative to the slipper clutch. is that wrong?
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  #9  
Old 12-16-2007, 04:07 PM
 
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Default RE: 07/08 600RR exhaust valve thingy?

Quote:
ORIGINAL: f3racer

ok wait i read somewhere that it was there to act as an alternative to the slipper clutch. is that wrong?
yeah pretty much,
you may be thinking of the IAC motor
it allows some air into the throttle bodies so that the rpms dont drop as dramatically. this would help with rev matching a little.


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yes, i guess maybe i can be a jerk, but i am tired of reading the same questions and hearing the same would be experts give out wrong info.
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  #10  
Old 12-16-2007, 09:44 PM
 
Join Date: Jun 2006
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Default RE: 07/08 600RR exhaust valve thingy?


Quote:
ORIGINAL: baxsom

Quote:
ORIGINAL: knightslugger

it isn't there for sound reduction. it's there to vary the exhaust pressure under different rider demands. exhaust pressure is important. don't disable it.
i so beg to differ
it has been proven time and time again on a dyno that this has nothing to do with performance.

with my own 600rr on a dyno there was no difference on a dyno of a run with the cables on or off

this has also been proven over and over again on the 1000rr as well

here are some articles for the uninformed
http://www.uucmotorwerks.com/html_pr...torquemyth.htm

this site says that a good way to lose power is with backpressure
http://auto.howstuffworks.com/question172.htm

this site says you need the most exhaust velocity possible with backpressure as close as possible to zero
http://www.miata.net/garage/KnowYourCar/S4_Back.html

this one gives a formula that for every 1" hg of back pressure you have you lose 1hp
http://www.thrashercharged.com/tech_htm/exhaust.shtm

a little off topic but this site says exhaust valves are there to warm the cat on a cold engine
http://lotusesprit.com.au/docs/Exhau...re%20Valve.pdf

so many others but they all pretty much say the same thing.
in fact the only sites i found where they say that any backpressure is good is where the pipe is too large and allows the gas velocity to slow down, or just some guys opinion with no scientific evidence
So how about that dyno sheet then? can you explain how the exhuast manifold valve works then? When is it open? When is it closed? is it open or closed when power is applied? how does this benefit the motorcycle? Federal sound level emissions remained unchained for the 2007 model year run so it wasn't because honda was trying to 'fly under the radar' for noise emissions. there was a reason.

So let's here it. i'm interested.
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Old 12-16-2007, 09:44 PM
 
 
 
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2005, 600, 600rr, cables, cbr, cbr600rr, close, dyno, exhaust, f3, honda, removing, rs5, sheets, valve, yoshimura


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