Wonder what's inside those Fishtail exhausts (Part 1)

[Eckypooh]

Took some pictures of the exhaust internals from the butterfly back, you can see some poor welding and overspill possibly restricting flow. only one baffle in there and the rest of the sound proofing is in the massive cavity of the fishtail itself.

 

[Eckypooh]

Part 2 everyone

 

[TodkaVonic]

Very cool

 

[Gaylord Poe]

Thank you for the pics. Fantastic information, many questions answered!!

 

[Eckypooh]

Plan for the winter is to cut a section underneath on the backside of the exhaust at entry to the Fishtail and at the first bracket. Then use a S/ST s-bend similar to the picture to smooth out the flow from the butter fly valve to the fishtail and make a new solid baffle with a hole in the middle with a pipe from the new s-bend to meet the baffle effectively halving the soundproofing in the exhaust. Then weld back up and polish. This is not my first rodeo on exhaust mods and is totally do able.
I will keep you posted in the spring on how it looks and sounds.

 

[R18Art]

How did you get in there!?!?!? Very cool to see. I'd like get a better sounding exhaust but would like to keep the stock fish tail look

 

[Eckypooh]

How did you get in there!?!?!? Very cool to see. I'd like get a better sounding exhaust but would like to keep the stock fish tail look

I used a endoscope with a 600mm extension and took snap shots every few inches, picture of equipment below. I also took a video but it is to large to post unless i can figure a way to compress it.

 

[Gerard]

You can send the video on YouTube and post the link.

Thanks for sharing.

 

[TodkaVonic]

I used a endoscope with a 600mm extension and took snap shots every few inches, picture of equipment below. I also took a video but it is to large to post unless i can figure a way to compress it.

No polyps. Repeat scope in 10 years.

 

[Black Dog]

One of many available on Amazon. https://www.amazon.com/Inspection-S...uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl
Use one all the time for inspecting the airplane engine.

 

[David R]

Thank you for that. I took apart my R1100RT. I removed the cat. the exhaust goes to the back of the muffler, to the front via tube then out the center, so the exhaust gasses go almost 3 lengths of the muffler.
After I removed the cat, the bike did not run any different and sounded worse.

David

 

[Moxie]

Question - I may have missed a post along the way, but what does the butter fly valve do?

 

[Eckypooh]

Exhaust butterfly valve is mainly used to silence or reduce noise emitted from the exhaust and they also help to smooth out pressure waves from the engine as well at various RPM’s. These valves are commonly used within the automotive industry, and they will be found working in all modern cars or motorbike exhausts.

When exhaust butterfly valves work “efficiently”, engines run quieter at low RPM and start much quicker and smoother. In addition, the heat from the exhaust manifolds will warm the fuel-air mixture for a cleaner start. They can be prone to seizing later in life which cause endless headaches to us mere mortals.

I am sure there are smarter guys out there than me that may be able to elaborate a bit more than me.

 

[Black Dog]

Holy Crap, Fish tails are full of

Part 2 everyone

Like looking down an outhouse or a portopotty.
fish farts

 

[Eckypooh]

At least you know what you are getting with a outhouse/portopotty

 

[Black Dog]

The difference is, I know what is inside my exhaust because I built them myself.
They sound exactly as I wanted them to because, I adjusted the components to tune the sound to what I desired.

 

[Moxie]

Sooo, removing the butter fly valve is NOT a good idea? Thought it might reduce the back-pressure.

 

[CB750]

Took some pictures of the exhaust internals from the butterfly back, you can see some poor welding and overspill possibly restricting flow. only one baffle in there and the rest of the sound proofing is in the massive cavity of the fishtail itself.

Any updates on your standard exhaust modification Eckypooh. I have a donor set of headers and fishtails to play with and am hoping for a bit more noise.

 

[33Cruzr]

Part 2 everyone

Thank you so much for the pics!! My priority is just to shorten the fishtail w/o altering the internals. I saw along the way about cutting, welding, and polishing. Is outer wall of the fishtail stainless steel or chromed mild steel? Is the back portion where you would cut and shorten, lined with perforated wall with sound deadening insulation in between? The whole project would be simpler if the outer wall was stainless steel so I can just weld and polish!!

 

[Rufus]

Just spotted this, great clear pictures, interesting to see what’s inside, impressed.