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A pipe question, but one i dont think has been asked

2K views 18 replies 7 participants last post by  Dragoon 
#1 ·
8)
:shock: With great pride I picked up the dragoon yesterday. It looks sweet for sure. As per previous posts, things were not perfect, by se la vie! However, I have some strange effects from this incident.

So, they replaced my 8 month old cobra pipes with the very same pipes from cobra. But they sound very different. I can’t figure out why. I looked at the old pipes and saw no difference (i.e. a hole saw mod or removed baffles). So, today I took it out for 100 miles to see if it was just them breaking in. I also took a close look at the mounting flanges hoping to see something obvious that might cause me to hear them differently. It does sound like I can hear it from the front of the engine. However, I have also noticed that I hear the engine much more now and I think that may have something with the fact that I am shielded substantially more from the wind with the Memphis shade product. I checked and all the plugs are working well and I have just as much power.

So, the quiz:

Part one, any ideas why that would be.

Part two, should I consider drilling some holes into my pipes or will that make them louder/worse/unbearable?

Part three, would a soap solution around the flanges show any leaks or do any damage?

Thanks,

Paul

P.S I cant tell over 200 miles total, but I think I have lost about 2-3 miles per gallon with the wider and bigger shield, but to me it is worth it.
 
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#2 ·
Please don't drill holes in perfectly good pipes.
 
#4 ·
i'd try a well worn us treasury note at the end of each pipe while idling to see if it ever gets sucked back in.

if so then you've likely got a leak at one of the crush gaskets at the head try tightening the nuts than hold the pipes in. if they used new gaskets(they are supposed to) they usually need a re torquing after a few heat cycles.

you can also do a close visual inspection where the pipe goes into the head on the front cyl to check for sooting the rear you can't really see.

as i found out with loud pipes it can be difficult to distinguish between exhaust and exhaust leak. not that i am knocking loud pipes or want any discussion on then just pointing out my own exeriance
 
#5 ·
White Knight said:
i'd try a well worn us treasury note at the end of each pipe while idling to see if it ever gets sucked back in.

if so then you've likely got a leak at one of the crush gaskets at the head try tightening the nuts than hold the pipes in. if they used new gaskets(they are supposed to) they usually need a re torquing after a few heat cycles.

you can also do a close visual inspection where the pipe goes into the head on the front cyl to check for sooting the rear you can't really see.

as i found out with loud pipes it can be difficult to distinguish between exhaust and exhaust leak. not that i am knocking loud pipes or want any discussion on then just pointing out my own exeriance

Thanks. i will try all of the above and call the dealership.

Cheers
 
#6 ·
Dragoon said:
However, I have also noticed that I hear the engine much more now and I think that may have something with the fact that I am shielded substantially more from the wind with the Memphis shade product.
You will absolutely hear more engine/exhaust sound with a windshield
than without a windshield.
Not only are you not hearing the wind rushing over and around your head,
the windshield is now a big sounding board for any noises that
are behind you.

I don't know how old your old pipes were, but also, newer pipes
will be more muted and less rumbly than older pipes.
Simple reason, baffle material is worn.
New baffles will be much more quiet than old baffles.
Don't know if those pipes have re-packable baffles, but if so,
that's a very likely scenerio.

Dragoon said:
Part two, should I consider drilling some holes into my pipes or will that make them louder/worse/unbearable?
I'd consider waiting a few months and few miles.
If it's just the baffles, like I said above, drilling holes is going to do
nothing but make it much louder once the baffles break in.

Dragoon said:
Part three, would a soap solution around the flanges show any leaks or do any damage?
Yes, but don't do it on a warm or hot engine. Do it when it's stone cold.
Never throw water on a hot engine. That's a good way to warp the head
and especially warp the flanges on the pipes.
 
#7 ·
Dragoon said:
chornbe said:
Please don't drill holes in perfectly good pipes.
I have no intention of doing so; I was merely asking the question. I would have thought you might have had some more insight then that.

Thanks a bunch.

Cheers

Paul
Sorry, I have no additional insight into what the difference would be other than the packing broke down over time in the other pipes. I just cringe at the idea of someone drilling holes in perfectly good, brand new pipes :)
 
#8 ·
I suspect it's all due to the windshield. I hear a totaly different bike when my sheild is off. When it's on you can hear engine sounds bounce off the sheild that you just cannot hear without one.

Something else you can do to check for leaks in the exhaust is to use either the baby powder or a small can of Co2. Squirt it around the fittings while the engine is running, should see it move around any leaks.
 
#9 ·
chornbe said:
Dragoon said:
chornbe said:
Please don't drill holes in perfectly good pipes.
I have no intention of doing so; I was merely asking the question. I would have thought you might have had some more insight then that.

Thanks a bunch.

Cheers

Paul
Sorry, I have no additional insight into what the difference would be other than the packing broke down over time in the other pipes. I just cringe at the idea of someone drilling holes in perfectly good, brand new pipes :)
I was just pulling your pin :D :D
 
#10 ·
I had an ACE 750 that got rear ended after about 16k miles - stock pipes. The tip of the pipe got bent up, 90 degrees straight up. Looked kinda funky so I picked up a set of used stock pipes from someone who'd swapped his out with very few miles on the bike for something a bit more "sporty." When I put them on, the bike had a totally different sound. Same windshield, same engine, no backdraft going back into the tailpipe (so gaskets were crushed properly & sealed). But, pipes with no miles on them have a different sound from pipes with 16k miles on them. The old pipes did seem to "mature" a bit over time & have a bit of a louder rumble. Made me realize that someone could easily want more sound out of a bike simply because his previous bike sounded louder than the stock exhaust because he'd ridden it until it matured. An interesting concept. Me? I like stock, but do think louder pipes sound cool (as long as I'm not riding behind them! :lol: ). No debate here, just saying that over time pipes DO "mature" a bit. Like the difference between 8 yr old Scotch & 20 yr old Scotch. Yummy.
 
#11 ·
Dragoon said:
8)
:shock:
Part one, any ideas why that would be.

Part two, should I consider drilling some holes into my pipes or will that make them louder/worse/unbearable?
Theres a theory that the pipes mellow as carbon deposits line the inside of the pipe ?
Why not just play with the baffle size first? I did some sound clips of various baffle sizes and also wrapping 4 inch cut down baffles with muffler padding.
http://www.hondashadow.net/forum/viewtopic.php?t=34113
 
#12 ·
Aero98 said:
Theres a theory that the pipes mellow as carbon deposits line the inside of the pipe ?
If that happened, the sound pitch would go up.
Low, deep rumbles come from big bore.
The smaller the diameter and shorter the pipes, the higher pitched the sound
will be.
The larger diameter and longer they are, the deeper they will sound.

It would take a LOT of carbon to change the sound enough to even notice.
 
#13 ·
litnin said:
Aero98 said:
Theres a theory that the pipes mellow as carbon deposits line the inside of the pipe ?
If that happened, the sound pitch would go up.
Low, deep rumbles come from big bore.
The smaller the diameter and shorter the pipes, the higher pitched the sound
will be.
The larger diameter and longer they are, the deeper they will sound.

It would take a LOT of carbon to change the sound enough to even notice.
the more carbon the more friction causing less velocity of sound passing through the pipes make lower sound waves. Hey I didnt say it was MY theory , you did note the "?" .

If you really want to get anal about sound qualities , join a guitar forum and discuss maple necks vs maple necks with rosewood fretboards vs small headstocks vs larger Fender 70s headstocks.

And how about ( lets not ) broaching your larger diameter pipe with X sized baffle vs non baffled vs covered baffle , its endless.
However I did find that with the cobra drags , cutting the 8 inch baffle down to 4 inches and then wrapping it with muffler packing made for a much more mellow tone then with just the 8 inch baffle , and pipe diameter did not change. soo......
:?:
:shock:
 
#14 ·
Interesting theory, carbon build up would create an absorbing layer of soft fuzzy junk on the baffles and inside of the pipes. This "could" change the tone, but how thick a coating would it take and how much it would change the tone is the question.

On a new clean pipe and baffle the sound would be bouncing off bare metal, an old fuzzy coated pipe would, (in theory), be a different sound.

Had the baffles out on mine and they are just perferorated sleeves, the carbon build up seems like it would act like a dampener of sorts.

Any acusticial engineers out there want to tackle this research project?
 
#15 ·
haha you really got me going now , what happens to the molecular structure of the metal as it heats and cools and heats and cools , does that start to change the tonal properties? A 2 inch pipe that you could blow air across sounds different if its made from plastic , glass , metal , - whats the diff there? molecular structure/vibration properties .

anyhow I hope dragoon starts with baffles first then moves up to the drilling of holes into said pipes.
:lol:
 
#18 ·
Aero98 said:
the more carbon the more friction causing less velocity of sound passing through the pipes make lower sound waves. Hey I didnt say it was MY theory , you did note the "?" .
I would say that is true is the carbon buildup in the pipes was not uniform
and had stalagtite and stalamite type structures inside.
But since the carbon build up is more of a uniform coating on the inside of the walls, the friction wouldn't be that much more than the walls of the pieps themselves.
The smaller diameter of the pipes, due to the carbon coating on the walls,
would actually increase the sound velocity.
I doubt very seriously it would be noticable to the human ear though.

Yeah, I noticed it wasn'y "your" theory... just throwing in some food for though.

Aero98 said:
If you really want to get anal about sound qualities , join a guitar forum and discuss maple necks vs maple necks with rosewood fretboards vs small headstocks vs larger Fender 70s headstocks.
I can imagine. Guitars are all about resonation. Change the material
that one is made of and you would completely change it's resonation characteristics.

Aero98 said:
haha you really got me going now , what happens to the molecular structure of the metal as it heats and cools and heats and cools , does that start to change the tonal properties? A 2 inch pipe that you could blow air across sounds different if its made from plastic , glass , metal , - whats the diff there? molecular structure/vibration properties .
Don't know about pipes, but I can tell you on a wind instrument (trumpet,
saxophone, tuba, etc...) that the tone properties change drastically
as the instrument increases and decreases in temperature.

At room temperature, if you tune a wind instrument to A440 Bflat,
temperature increase will cause the note to go flat and temperature
decrease will cause it to go sharp.

I would imagine the same thing happens with exhaust,
however, the amount you would notice it probably won't be as much
as it would be with a 'more refined" musical instrument.
 
#19 ·
I am told that their will be a slight change in tone (up or down was not mentioned). So, for now, I will just drive the bike like it is and in 5k will revisit the idea. I am not fond of drilling any holes and don’t want to get into changing baffles, at least not while they are brand new.

Thanks for the very interesting thread.

Cheers

Dragoon
 
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