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Yep. It certainly looks like you lose the exhaust valve with a slip on.

And the cables are what open and close the valve... :wink:

Maybe Alien10 or someone else with an '08 and a slip on can tell you what they did with the cables.




Chris
 

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There's two cables that connect from the butterfly valve (if you look close in a stock picture behind the right footpeg shield) there are two cable and they connect to a mechanism under the seat. You simply take them off w/ the canister when you put on a slip-on.
 

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Discussion Starter #6
That would be good to know!

Because as we all know, exup indeed helps to get more power "down low"
 

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the cables run from underneath the main seat. There is a servo that controls those cables. The cables run down the frame to the exhaust controlling the valve. Once you take the cable out, its open all the time and the ECU via the servo can't control it anymore. If you take the entire servo out theres going to be a FI light error. If you take just the cables out, no error, and valve stays open. Simple!

Oh and yeah, just replacing the muffler will get rid of the valve as well!
 

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Discussion Starter #8
There's two cables that connect from the butterfly valve (if you look close in a stock picture behind the right footpeg shield) there are two cable and they connect to a mechanism under the seat. You simply take them off w/ the canister when you put on a slip-on.


...and you do not have "exup" (that valve) anymore. Right? It is there, but it is open all the time. So you loose some torque at lower rpms?
 

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La Flama Blanca
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...and you do not have "exup" (that valve) anymore. Right? It is there, but it is open all the time. So you loose some torque at lower rpms?

EXup is a yamaha term not a kawasai, on the Yamahas, the "exup" serves a different purpose and if you think about it, its much further up the exhuast, closer to the head, the valve on the kawi, IMHO, is more about noise control than it is about low end power management, not saying it has no effect on bottom end, but much les of an effect as the yamaha valving, at least the earlier EXup systems, as thats what i am familiar with.
 

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Discussion Starter #10 (Edited)
And whats the difference between Yamaha and Kawasaki versions? Its the same simple valve that is partially open at lower rpms (to increase backpressure) and then fully open above 5000rpm or so...?
 

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La Flama Blanca
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And whats the difference between Yamaha and Kawasaki versions? Its the same simple valve that is partially open at lower rpms (to get more vacuum efect) and then fully open above 5000rpm or so...?
Like I said, I am not that familiar with the 04-08 yamahas, valve, but in the earlier bikes was the valve not located further up the exhaust close to the head, in the collector? I don't own a yamaha so I don't know for sure, but in Kawis, that exhaust valve is more about noise control, there have been a ton of threads on this and its been beat to death, no one has really produced any hard evidece that the valve does anything besides quite the exhuast down, there have been some dynos produced that showed no difference and there have been guys that claim a ton of SOP difference. Irrelivent to me, cause every bike I will own will have a full system and a powercommander.
 

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Discussion Starter #12
Yes on Yamahas it was closer, right in the middle of whole exhaust tube(s).

I check on this site and dynos were made with fully open throttle...i wonder what happens with partially open throttle...then again, probably that difference isn't big.

At what rpms does this valve open fully? 7k really? or lower? Anyone know?
 

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Like I said, I am not that familiar with the 04-08 yamahas, valve, but in the earlier bikes was the valve not located further up the exhaust close to the head, in the collector? I don't own a yamaha so I don't know for sure, but in Kawis, that exhaust valve is more about noise control, there have been a ton of threads on this and its been beat to death, no one has really produced any hard evidece that the valve does anything besides quite the exhuast down, there have been some dynos produced that showed no difference and there have been guys that claim a ton of SOP difference. Irrelivent to me, cause every bike I will own will have a full system and a powercommander.
I still have a VCR recording of the 1990 Daytona Superbike Race where Dave Sadowski riding the Vance and Hines Yamaha OWO1 beat Honda RC-30 mounted Randy Renfro.

During the pre show they showed video footage of a cutaway of the EXUP valve used on the Yamaha. It was 4 seperate buttery flys located at the point where the 4 joined into 1 and they specificaly stated it was used to increase uuummmppphhh coming off the corners by varying back pressure.

Vance and Hines had these on their superbikes. Yamaha had an exclusive patent on this technology I believe until 2003 but I could be wrong on the year.

Thats why no one else was using it.

So YES 9R to 10R is correct about EXUP being located further up the head pipes and it was for power and not noise purposes or V&H wouldnt had it on their race bikes.

This current use of the butterflys upstream may perform the same concept, and or it may be for noise. I dont know.

BUT Yes, you loose it on the 08 with the most basic of slip ons.

Maybe I will get a digital camera one day and film this VCR recording and put on you tube. What V&H was using was a very hi tech and very trick set of 4 individual butterflys and not the basic single unit we have now.

My guess, it is used now for noise control.

JJ
 

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Discussion Starter #14
Did you feel any difference from 1500rpm to 4000rpm riding stock bike and then riding with slipon? Especially at half open throttle? Or is it absolutely the same
 

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The valve is eliminated if you change to any slip on. I didn't noitce any major low end changes - the bike is a bit soft down low anyway.
 

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I haven't road mine with the valve disconnected,....yet. Maybe will try that this weekend. Go out and ride a few miles, then disconnect the cable, and let it spring open, then ride again back to back.

Stories I have read on this forum of people doing this on Gen 1 & 2's state it is more powerful down low with valve disconnected. Might be placebo effect though. :dontknow:

JJ
 

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Discussion Starter #17
Some say (like Alien10) that bike is a bit soft, others say its more powerfull download low...

:dontknow:
 

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La Flama Blanca
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Some say (like Alien10) that bike is a bit soft, others say its more powerfull download low...

:dontknow:
Might be that Alien has a gen 1 and a gen 3, my gen 1 feels a little soft down low compared to my gen 2, the gen 2 really has a monster of a motor, it is simply a mid range monster, that is the one thing all the mags gave it credit for, it has the best liter bike engine overall, even though the 1K may have had a couple more peak hp, look at any comparo graph and it will show the same thing, the kawi motor defiantly has the best low end and mid range, so there lies the discrepancy.
 

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no wonder the stock 08 exhaust is so restrictive, looks at all those baffles, it's a maze for the gases to find their way out :(
 

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Discussion Starter #20
Might be that Alien has a gen 1 and a gen 3, my gen 1 feels a little soft down low compared to my gen 2, the gen 2 really has a monster of a motor, it is simply a mid range monster, that is the one thing all the mags gave it credit for, it has the best liter bike engine overall, even though the 1K may have had a couple more peak hp, look at any comparo graph and it will show the same thing, the kawi motor defiantly has the best low end and mid range, so there lies the discrepancy.
Well i think its clear to everyone that we are talking about valve on/off on the same bike :)
 
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