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Exhaust Servo

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So I have been going through all the muffler / servo threads and reading about the different approaches and results all you good people have posted. So I really like the uniqueness of the fishtails but hate the anticlimax when you start that beast of an engine. With that in mind, I have received these bad boys today and the fishtails are currently with Matt at www.therealtoyshop.co.uk for the ‘stage 2’ mod. I’m hoping that the combo of open servo and open fishtails will generate decent sound. Not looking for obnoxious, just want to hear exhaust notes and not just engine noise at idle and when riding. Will post back here with updates once fitted.
 

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Jmcgints said:
So I have been going through all the muffler / servo threads and reading about the different approaches and results all you good people have posted. So I really like the uniqueness of the fishtails but hate the anticlimax when you start that beast of an engine. With that in mind, I have received these bad boys today and the fishtails are currently with Matt at www.therealtoyshop.co.uk for the ‘stage 2’ mod. I’m hoping that the combo of open servo and open fishtails will generate decent sound. Not looking for obnoxious, just want to hear exhaust notes and not just engine noise at idle and when riding. Will post back here with updates once fitted.
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When the mufflers are returned to you can you take some detailed pictures of what they’ve done before installing them on the bike?
 
I can’t recall where I saw it but I have seen the gist before. They cut open the silencer underneath near to the link pipe join, (so you can’t easily see the cut) then rake out the sound deadening material and weld it up again. Maybe YouTube ? There’s little to no restriction in the Fishtails anyway. The flapper does most noise reduction. It’s a very personal choice but I do like mine bog standard.
 
Rufus said:
I can’t recall where I saw it but I have seen the gist before. They cut open the silencer underneath near to the link pipe join, (so you can’t easily see the cut) then rake out the sound deadening material and weld it up again. Maybe YouTube ? There’s little to no restriction in the Fishtails anyway. The flapper does most noise reduction. It’s a very personal choice but I do like mine bog standard.
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Not true.

Although the baffles appear small they do restrict the velocity thus reducing the sound. There is a ton of surface area in the fishtails that dramatically reduces the noise. The flappers are open at sig throttle anyway.

With flapper removal you will get some more noise at idle and part throttle. Not crazy tho due to the above mentioned fishtails sound proofing. No change at heavy throttle as they are open anyway.

To really understand.

1) Remove the fishtails
2) start bike. Slight throttle blip. Listen
3) turn off bike
4) open flappers
5) start bike. Slight throttle blip. Listen.

Now do the same with the fishies on. You will then understand the significance of those silencers.
 
Rufus said:
I can’t recall where I saw it but I have seen the gist before. They cut open the silencer underneath near to the link pipe join, (so you can’t easily see the cut) then rake out the sound deadening material and weld it up again. Maybe YouTube ? There’s little to no restriction in the Fishtails anyway. The flapper does most noise reduction. It’s a very personal choice but I do like mine bog standard.
Click to expand...
I ran an endoscope through the mufflers and there is baffle with 3 holes in it. I’m sure that contributes quite a bit to the sound deadening.

1682009687061.webp
 
Gr8adv said:
Not true.

Although the baffles appear small they do restrict the velocity thus reducing the sound. There is a ton of surface area in the fishtails that dramatically reduces the noise. The flappers are open at sig throttle anyway.

With flapper removal you will get some more noise at idle and part throttle. Not crazy tho due to the above mentioned fishtails sound proofing. No change at heavy throttle as they are open anyway.

To really understand.

1) Remove the fishtails
2) start bike. Slight throttle blip. Listen
3) turn off bike
4) open flappers
5) start bike. Slight throttle blip. Listen.

Now do the same with the fishies on. You will then understand the significance of those silencers.
Click to expand...
Fair point but loudness alone does not necessarily mean a ‘nice’ or a pleasing tone to the ear. I don’t think the boxer engine sounds particularly nice TBH, it’s quite a flat farty sound. I like what BMW have done to tune the sound into something pleasant albeit it’s on the quieter side, I’ll take that compromise.
 
Hi MilwDave, Yea possibly will do to some very small degree but the baffle also provides structural integrity. The exhausts will have been computer designed and flow modeled to ensure they work well across the whole operating range of the engine (within legal parameters obviously). That’s gas velocity, harmonics, scavenging, sound, durability etc. The R18 is so under stressed and low revving I doubt removing that baffle or sound deadening makes much, if any positive difference to actual performance, in fact it might actually make things worse running a more open pipe (without proper compensation elsewhere). There’s the placebo effect of louder=better. Not necessarily so.
 
Rufus said:
Fair point but loudness alone does not necessarily mean a ‘nice’ or a pleasing tone to the ear. I don’t think the boxer engine sounds particularly nice TBH, it’s quite a flat farty sound. I like what BMW have done to tune the sound into something pleasant albeit it’s on the quieter side, I’ll take that compromise.
Click to expand...
A boxer engine will never sound like the V-twins we have grown accustomed to in the market segment the R18 is now a part of. But it does sound good uncorked. Now how much volume sounds good is a personal preference.
I’m running open shorty tailpipes right now while the fishtails are being worked on. They actually sound pretty good.
IMG_3104.webp
 
Rufus said:
Fair point but loudness alone does not necessarily mean a ‘nice’ or a pleasing tone to the ear. I don’t think the boxer engine sounds particularly nice TBH, it’s quite a flat farty sound. I like what BMW have done to tune the sound into something pleasant albeit it’s on the quieter side, I’ll take that compromise.
Click to expand...
I tend to disagree here ... although I am running aftermarket slip-ons and not mod OEM pipes, I really like the sound ... yes, she does not have the V-Twin pattad noise but when mine is up to temp she lopes nicely in idle ... has a good deep sound when riding and when I get on it, she has a mean growl to her voice ... but maybe that's just me ;)
 
They can sound SWEET. I have deleted the cat, and removed the baffle and flappers. They are not idiot loud. Just lovely.

If anyone has a stock fishy in seattle jt would be great to do a side by side video. Let me know.
 
I have the Fishtails back and here's my SitRep:

With the servo plugs installed and the Fishtails being basically as open as they can be, there is a much better acoustic. I will try and upload a sound recording with db numbers. It is by no means Harley loud, or even what someone might even class as 'loud' but on idle and when riding at any speed, I can hear the exhaust brapping (is that a word?) over the sound of the engine when in the saddle, which is the key. For me, the standard exhaust note is fine if you're standing behind the bike, but sit in the saddle and all I could hear was the engine noise. In short, it sounds a bit more like a bull than a heifer now.

The electronics / O2 sensor can adjust air / fuel for the open mufflers, Just leave it idling for 10mins and it will adjust accordingly - cat delete or full systems such as Zard etc would require a remap / tune I assume? As you can see from the images (only have my phone camera so sorry they aren't more detailed) the pipes are pretty much fully open now and the welds are, well, they are what they are. They are neat & tidy and run along the bottom inside seam so not noticeable when on the bike. However, some of the surrounding chrome is slightly impacted by what I assume is the heat of the plasma cutter and or welder. Again these little bubbles are on the inside seam so not something you can see.

20230429_072901219_iOS.webp20230429_072746076_iOS.webp20230429_072750925_iOS.webp
 
MilwDave said:
A boxer engine will never sound like the V-twins we have grown accustomed to in the market segment the R18 is now a part of. But it does sound good uncorked. Now how much volume sounds good is a personal preference.
I’m running open shorty tailpipes right now while the fishtails are being worked on. They actually sound pretty good.
View attachment 9732
Click to expand...
Can I ask what shorties are in the pic? Because of the pipe config, the one's I've seen always seem to have a significant gap where the pipe slides on and heat shield. But yours seem to marry up nicely.
 
Anyone have a before and after or even just an after of what the exhaust sounds like after opening the baffles?
 
Jmcgints said:
Can I ask what shorties are in the pic? Because of the pipe config, the one's I've seen always seem to have a significant gap where the pipe slides on and heat shield. But yours seem to marry up nicely.
Click to expand...
X2 on this. Almost looks like the inexpensive short slip ons you see at oreillys or auto zone for automobiles. Looks pretty good imo👍🏻
 
Jmcgints said:
Can I ask what shorties are in the pic? Because of the pipe config, the one's I've seen always seem to have a significant gap where the pipe slides on and heat shield. But yours seem to marry up nicely.
Click to expand...
There is a gap but the pegs are blocking it. The factory heat shield on the front header has a curve that creates the gap. I bought a short chrome heat shield on Amazon that tucks beneath it.

https://radiantcycles.com/
 
Jmcgints said:
I have the Fishtails back and here's my SitRep:

With the servo plugs installed and the Fishtails being basically as open as they can be, there is a much better acoustic. I will try and upload a sound recording with db numbers. It is by no means Harley loud, or even what someone might even class as 'loud' but on idle and when riding at any speed, I can hear the exhaust brapping (is that a word?) over the sound of the engine when in the saddle, which is the key. For me, the standard exhaust note is fine if you're standing behind the bike, but sit in the saddle and all I could hear was the engine noise. In short, it sounds a bit more like a bull than a heifer now.

The electronics / O2 sensor can adjust air / fuel for the open mufflers, Just leave it idling for 10mins and it will adjust accordingly - cat delete or full systems such as Zard etc would require a remap / tune I assume? As you can see from the images (only have my phone camera so sorry they aren't more detailed) the pipes are pretty much fully open now and the welds are, well, they are what they are. They are neat & tidy and run along the bottom inside seam so not noticeable when on the bike. However, some of the surrounding chrome is slightly impacted by what I assume is the heat of the plasma cutter and or welder. Again these little bubbles are on the inside seam so not something you can see.

View attachment 9849View attachment 9850View attachment 9851
Click to expand...
I’m looking forward to hearing them!
 
I cant imagine the sound is much different but I could be wrong.
(Talking about the servo mod)
I have heard the shorty pipes in real life and they are a bit loud.
:)
 
Jmcgints said:
Can I ask what shorties are in the pic? Because of the pipe config, the one's I've seen always seem to have a significant gap where the pipe slides on and heat shield. But yours seem to marry up nicely.
Click to expand...
Just as an update to the above. I used a DB app on my phone, which I guess you could use as a comparison with standard pipes. With the phone on the seat and the bike idling outside, it was reading 82db. With the phone in my jeans pocket whilst riding spiritedly it peaked at 126db. The only issue I've found with sound recordings is that they are great for hearing the 'type' of sound an exhaust makes but very subjective on loudness i.e. has it been recorded inside or outside? Sitting on the bike, standing next to the bike or stood at the rear of the bike. Six inches from the rear of the pipes or stood a couple of meters away etc.
 
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