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Discussion Starter · #1 ·
Is the Exhaust Butterfly Valve integral with the muffler or a separate piece?

i.e. If you take off the muffler to replace it with a different one, does the Butterfly Valve come off with it?

I'd like to consider a different muffler, but want to keep the Butterfly Valve.

I've tried to study the service manual drawings, but they don't make it clear if the Butterfly Valve is integral to the muffler or not.

Jim G
 

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Discussion Starter · #3 ·
Thank-you, KevA. I suspected that. It really limits what can be done to the exhaust at all, as removal of that Exhaust Butterfly Valve will likely significantly adversely affect low and mid range torque and therefore power.

Jim G
 

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It will effect the performance but not Significantly tbh.
Most Folks fitting an aftermarket end can/Full system will pop a decent Air Filter in and get it mapped to get the best out of the Bike.
 

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Discussion Starter · #5 ·
I am satisfied with the OEM power level, as my Vancouver Island riding environment is posted mostly at 80 KPH = 50 MPH or less, but I'd hate to lose any midrange power out of the ZX-6R's already modest midrange.

So, an ECU reflash is not in the plans, but if I do replace the OEM muffler, I guess I'll need to install a Butterfly Eliminator device to prevent a trouble code.

My motivation in replacing the muffler is NOT to gain power, but rather to eliminate some weight that lives near the top of this top-heavy notorcycle! I figure I can lose 3.5 to 4 lb of weight via a Lithium versus AGM battery, and I was hoping I could lose a bit more weight via a Carbon Fiber muffler versus the OEM muffler. I've also of course already removed the passenger footpeg assembles as I never carry a passenger.

How much does the OEM muffler assembly (i.e. ONLY the part of the exhaust that would be replaced by a slip-on) weigh? If it's only say 2 lb, then a repalcement is not worth it. But if it weighs 10 lb, then yeah, a replacement would make a big difference in both handling and just rolling the motorcycle around the garage and driveway more safely!

How much does the muffler assembly (i.e. ONLY the part of the exhaust that would be replaced by a slip-on) weigh?

Jim G
 

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Use a servo buddy. Kawasaki Brad is the place to go. You can remove all the gubbins that way. As for affecting power… marginal…. The servo is actually there to conform to euro 5 regs for the emmisions as well as quieten it down for the pass by noise tests which have been lowered. It will run lean without a flash tune though Iirc a flash on a zx6r is circa 300 and worth every dollar.
 

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Discussion Starter · #7 ·
Use a servo buddy. Kawasaki Brad is the place to go. You can remove all the gubbins that way. As for affecting power… marginal…. The servo is actually there to conform to euro 5 regs for the emmisions as well as quieten it down for the pass by noise tests which have been lowered. It will run lean without a flash tune though Iirc a flash on a zx6r is circa 300 and worth every dollar.
Euro 5 did not exist in 2008. I found out through further research that it was the tightened California or U.S exhaust NOISE regulations that apparently surprised Kawasaki, and their ill-advised "solution" was apparently to use the butterfly valve which had already been specced as a mid-range power improver in a partially closed position at rpm above 12,000 to limit the NOISE level. The Jumper Mod undoes that power decrease above 12,000 rpm.

Jim G
 

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The mid range gains were a marketing ploy. The regs did not come in but were being worked on and manufacturers aware long before. The mild gain is related to the wave propagation of the exhaust gas and it helps pull out the gas improving torque . The problem always was that it’s only a very small and I mean very small window of gain due to the speed of sound and the return of the exhaust gas being directly proportional to the LENGTH of the exhaust and therefore a select range that it’s effective . They labelled it a performance gain to POLISH A TURD. The torque curve as standard you will notice is not smooth. With a tune and removal of the servo it smooths it out. I was an engineer at Bentley and Jaguar in the uk.
 

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Discussion Starter · #9 ·
The mid range gains were a marketing ploy. The regs did not come in but were being worked on and manufacturers aware long before. The mild gain is related to the wave propagation of the exhaust gas and it helps pull out the gas improving torque . The problem always was that it’s only a very small and I mean very small window of gain due to the speed of sound and the return of the exhaust gas being directly proportional to the LENGTH of the exhaust and therefore a select range that it’s effective . They labelled it a performance gain to POLISH A TURD. The torque curve as standard you will notice is not smooth. With a tune and removal of the servo it smooths it out. I was an engineer at Bentley and Jaguar in the uk.
So if you remove the butterfly and its servo, and buy a device that removes the no-servo trouble code, but do not buy a reflash, you suffer no adverse effects from removing the servo and butterfly?

Jim G
 

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It will run a little lean. Ive found that no map will burn plugs a little quicker. If you change anything on a bike affecting airflow it’s always best to remap as the air fuel ratio always shifts a little from ideal. The benefits of a map are huge. I highly recommend getting remaps.
 

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Discussion Starter · #11 ·
It will run a little lean. Ive found that no map will burn plugs a little quicker. If you change anything on a bike affecting airflow it’s always best to remap as the air fuel ratio always shifts a little from ideal. The benefits of a map are huge. I highly recommend getting remaps.
Ok, thanks! Getting a map to here on Vancouver Island, even by mail, is a very slow return process with COVID shipping & Customs delays. :(

Jim G
 

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One of my buddy lives out there and drifts bMW
‘S has the same issue with parts. You could do FT ECU and load map yourself. OR bren tuning have a module they can send out to flash with.
 

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Discussion Starter · #13 ·
One of my buddy lives out there and drifts bMW
‘S has the same issue with parts. You could do FT ECU and load map yourself. OR bren tuning have a module they can send out to flash with.
Here in Canada, the physical setup required to do FTECU costs more than a custom tune! And I can't use a PC based method because I gave up on Pcs and went to Mac in 2010! The cost of the whole FTECU thing is simply not worth it to me.

Jim G
 

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Discussion Starter · #15 ·
I also just checked the service manual, searching for "ECU Removal":

ECU Removal

•Remove:
Muffler Body
Seat Cover (see Muffler Body Removal in the Engine
Top End chapter)
Battery (see Battery Removal in the Electrical System chapter)
Rear Fender [A] (see Flap and Rear Fender Removal in the Frame chapter)
•Pull out ECU with rubber protector.

•Remove:
ECU Lead Connectors [A]
Rubber Protector
ECU [C]

Unreal.

This does NOT sound either fast or easy (especially the removal of the muffler which in turn requires removal of the entire rear end of the motorcycle) . . :)

Just like on my Kawasaki Z400, the Kawasaki lawyers apparently did not want owners playing with the ECU!

Jim G
 

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It’s not as hard as you think to be honest. You must have some cold months it’s going to be sat around anyway. It’s worth the grind. They hold
Back the engines so so much with the standard maps.
 

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Discussion Starter · #17 ·
Hey, one of the reasons we moved here a few years ago is that you can ride all winter! Yes, there are many cold and rainy days here, and even snow very occasionally, but every winter so far I have been able to ride at least a few times per month, so my bikes are never "down for the winter". When I was younger, I lived in both Winnipeg, Manitoba and Minneapolis, Minnesota, and THERE I DID have winter downtime! I also lived for a time in Texas where I could ride almost every day of the year.

Jim G
 
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