Muffler Disassembly

If it's broken or just needs tweaked

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Pinhead
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Muffler Disassembly

Postby Pinhead » Wed May 02, 2007 12:33 am

How do I pull this thing out (circled in red)? I've pulled, twisted, cranked, hammered, and pretty much every combination and it won't come out.

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cb650
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Postby cb650 » Wed May 02, 2007 5:59 pm

I believe it is internally welded while assembeled so youll just have to keep hammering untill it breaks free.




Terry

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holysmokes
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Postby holysmokes » Wed May 02, 2007 6:57 pm

why would you want to remove the baffles

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Volker_P
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Postby Volker_P » Thu May 03, 2007 6:33 am

Welcome here! :D
I never opened a CB650 exhaust but I would guess you will not get the insert (probably with an array of reflection plates below) past the outer ring.
So you first have to remove the outer ring but that might be not sufficient as I would not bet that the insert is not welded or fixed somehow at its other ending, too.
If you like to try it anyway, please post the result and some pics here. :roll:

Pinhead
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Postby Pinhead » Fri May 04, 2007 10:27 pm

Well, I got them out. They're basically "glass packs" that are about 6 inches long. I just had to do a heck of a lot of pulling to get them out. They're simply shoved into a hole that's about the same size (tight fit). The steel plate with the 3 rivets is all that was holding it all together (other than carbon). I'm going to try to make my own glass pack that will flow much more than the stock ones do. It should sound about the same as stock (maybe a little deeper) but offer less restriction. The picture with the red, yellow and blue circles shows how the tail baffle works. The red circle is the exhaust coming from the front of the muffler. The blue one is where the exhaust is reflected back into the chamber behind it, and the yellow circle is where the inserts fit, ultimately leading to the exit of the muffler system.

I'll probably run them only for a short while, though, because I love the sound!

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Chris
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Postby Chris » Sat May 05, 2007 1:56 am

Have you noticed any change in performance with those removed? Could you record the sound and share it with the rest of us? My 4 into 4 pipes are getting pretty bad and I'm exploring my options before the time comes when I absolutely must replace them. 4 into 2 with turnouts is one idea that I've been tossing around. When I finally find a replacement, I might fool around some with the current setup like you are now.
1980 CB650c

Pinhead
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Postby Pinhead » Sat May 05, 2007 3:42 pm

I'll try to get a recording, but all I have is my camera/video phone (I'll have to figure out how to keep the sound from over driving the microphone). It's not nearly as loud as open headers, but obviously louder than stock. It doesn't have any "buzz" to it at high revs, and has kind of a resonating deep tone to it. Hopefully I'll be able to get a decent recording.

The performance seems to be up all the way around, though I recently side-gapped my spark plugs; the combination of the two is probably where the performance is coming from. I'll see how where gas mileage goes after I run a tank through it.

Edit: If you're careful you could grind the rivets off of the back plate and twist the rear baffle out without damaging anything. If you don't like the sound you could simply put it back in and rive it all back together. Just be sure to twist and try not to bend up the plate up like I did. It's not screwed in, just takes quite a bit of pulling/twisting to loose the carbon deposits.

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Ibsen
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Postby Ibsen » Sat May 05, 2007 5:07 pm

I get an average of 4.6L/100km or approx 50mpg with the drilled mufflers on my bike.

Pinhead
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Postby Pinhead » Sat May 05, 2007 5:46 pm

Ibsen wrote:I get an average of 4.6L/100km or approx 50mpg with the drilled mufflers on my bike.


Is that highway, city, or mixed driving? I made a 5 hour trip to my parents' house on I-70 a couple of weeks ago and it got 47mpg both ways going 70mph. Driving around town I usually manage 55 to 60mpg. I'm willing to bet my mileage will go up because it's running quite a bit better (that is, if I can keep it away from WOT...). Then again, it'll be impossible to know if it's the side-gapped plugs or the exhaust that will ultimately make the difference.

I tried getting a sound recording of my bike on my way to work today but my phone's microphone gets completely overloaded by the volume. I'm going to try to cover the microphone to try to limit the sensitivity.

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Ibsen
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Postby Ibsen » Sun May 06, 2007 2:28 am

That's mostly 55~60mph cruising. I don't ride it much in town so I don't know what the mileage would be there.

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Volker_P
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Postby Volker_P » Mon May 07, 2007 12:57 am

Thanks for the pictures! :D
Does it look like it was welded or fixed otherwise to the center hole (yellow circle)?
If you just can pull it out through the center hole as a close fit (without removing anything else), I wonder about the connection to the rivets and how to rive it back again.
Or did I misunderstand and you also took out the center ring with the holes for the rivets (which would mean pictures 2 and 3 show parts that are off the exhaust pipe)? But then I would expect the outer ring and the 3-hole insert should be separable to get past the rivet counterpart to pull them from the exhaust tube. Maybe an overwiev picture could help. :)

Pinhead
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Postby Pinhead » Mon May 07, 2007 1:12 am

The last two pictures are looking into the tail of the exhaust pipe. In the very first pic (post #1), the insert is what is circled. That pulled straight out. It wasn't welded on the inside.

I should have gotten pictures of the tear-apart process, but I'll try to explain it. If you could post a pic of the end of your stock exhaust, I could probably explain it more clearly.

Basically, if you grind off the three rivets on the end of your mufflers, the steel plate (the part that's not chromed, isn't in any of my pictures) should twist and pull straight out. The glass packs are welded to that plate, and will come out with it. I bent mine all up trying to get it out, because I wasn't sure if it was welded on the inside or not. If you're going to remove it, your best bet would be to spray some WD-40 or something similar on the inside of the insert to try to loosen it up. You'll probably have to do more twisting than pulling, but if you could stick something inside the throat of the insert, you should be able to pull straight out from there (with a little wiggling and turning).

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kbailey
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side gap?

Postby kbailey » Mon May 07, 2007 1:22 am

sorry for my ignorance but you talk about side gapping your plugs. what exactly is that, I've never heard the term before?

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Volker_P
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Postby Volker_P » Mon May 07, 2007 1:43 am

Thanks!
Now I think I understand. So the steel plate was already missing in your first posting's picture. If you had managed to pull the thing out in one piece, you would have got the "glass pack" with a steel plate at its end. Something looking like a hollow mushroom with holes for rivets. :D

Pinhead
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Re: side gap?

Postby Pinhead » Mon May 07, 2007 1:54 am

Volker_P wrote:Thanks!
Now I think I understand. So the steel plate was already missing in your first posting's picture. If you had managed to pull the thing out in one piece, you would have got the "glass pack" with a steel plate at its end. Something looking like a hollow mushroom with holes for rivets. :D


Exactly right. :)

kbailey wrote:sorry for my ignorance but you talk about side gapping your plugs. what exactly is that, I've never heard the term before?


http://performanceunlimited.com/documen ... pping.html :)


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