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Universal muffler installation

This is a discussion on Universal muffler installation within the Technical forums, part of the Caferacer.net Forums category; Hey all. I've been having a bit of a pain in installing a universal muffler on an 80s airhead. I feel a bit like a ...

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  1. #1
    Junior Member 4into1's Avatar
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    Universal muffler installation

    Hey all. I've been having a bit of a pain in installing a universal muffler on an 80s airhead.
    I feel a bit like a noob here, as I've done plenty of other mods to the bike..but I'm not sure the correct way to install and I've had no luck in googling.

    I have a set of these
    https://www.caferacerwebshop.com/en/...lat-black.html

    The diameter of the pipe is significantly less than the diameter of the cone inlet.
    They've included some inlet inserts, but I'm not sure if I should nest them (inside one another) or what the best way is to install.
    Are they meant to go inside the cone or outside?

    Even clamping down all the way, I've found that I can easily slip the cone right off.
    I'll figure this out eventually, but I expect that I'm just being a dumbass and someone can tell me how it's done here.

    Thanks!

  2. #2
    jcw
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    Senior Member jcw's Avatar
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    Spam...

  3. #3
    Senior Member TrialsRider's Avatar
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    Quote Originally Posted by jcw View Post
    Spam...
    You think so? But he kinda slammed the universal product for not really being universal so that would be negative advertising :| I'm confused.

    Asbestos wrap would work perfect but your bike would become a toxic waste site, fibreglass cloth and some muffler or chimney cement, I've used that as a cheap muffler gasket before.

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  5. #4
    Senior Member DesmoDog's Avatar
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    Buy a muffler that fits the pipe, those adapters are shit and won't seal.

    Or... find a muffler shop that will make an adapter that fits the ID of the muffler on one end and the OD of the pipe on the other. They can slot the end of it that fits over the pipe. Then have that TIG welded to the muffler, it won't destory the chrome.

    Post #30 has a picture of this.

    https://www.caferacer.net/forum/tech...muffler-3.html
    -Craig
    The Mighty Monza Jr. Thread: https://www.caferacer.net/forum/proje...r-project.html

  6. #5
    Senior Member Geeto67's Avatar
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    I have those exact mufflers on my 1986 R80 airhead.

    my bike has the dual outlet catalytic converter so I mounted them to it directly. I did have to use a pipe expander on the muffler to fit the cat outlet. I was going to mount it to the head pipe with the shims they included, but didn't end up doing it for the same reason you are running into, with two shims it wouldn't tighten down, but with three shims it wouldn't go on at all.

    I am not super thrilled with the the shims that come with the muffler, they can be made to work, but if I were you I would go to an exhaust shop with both pipes and have them match up an adapter. They go on the inside of the muffler and the outside of the header, and they nest and index with a tab into each other so the break in them aren't aligned and cause a leak. If you need to adjust their size, you can use hose clamps of various sizes to adjust down the orifice size of the muffler and the shims.

    one last thing, I didn't think the finish on the mufflers was all that good, it scratched way to easily and was super thin. I repainted mine before install with a semi-gloss high heat paint which has made them more durable, more rust resistant, and makes them look better.
    Last edited by Geeto67; 06-17-2019 at 09:25 AM.
    TrialsRider and 4into1 like this.
    Ever tried. Ever failed. No matter. Try Again. Fail again. Fail better.
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  7. #6
    Junior Member 4into1's Avatar
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    Thanks Geeto. Exactly what I was looking for. You have any photos of it finished? I agree that the finish probably isn't the best...they're also pretty cheap. I mostly needed something to replace a stock muffler that rusted off. Did you get to keep the center stand? I have the exact same bike 86 R80. I am currently bypassing the converter box, which I'm not sure is good or bad yet. It's a cleaner look and more similar to the custom R80s I've seen online.

  8. #7
    Senior Member Geeto67's Avatar
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    I'll take some pictures this afternoon.

    my stock mufflers rotted and cracked off as well, which is why I went with it.

    yes I kept both my center and aftermarket side stand.

    Everyone I have spoken to that connected it to the head pipes directly tells me they had an exhaust shop make a small adapter. I think if I had the pipe expander at the time I was trying to fit it to the head pipe, I could have made it work using all three adapters, but I would have lost my side stand as it wouldn't clear. I would have also had to make a stop for the center stand for when it was up, but that's not difficult, I used to do that on hondas with custom exhaust using angle iron. Keeping the side stand was my reason for deciding to keep the cat, I painted it black and to be honest it's hardly noticeable.

    this is the pipe expander I used:
    https://www.harborfreight.com/Medium...der-63703.html

    I borrowed it from a friend, because it had horrible reviews and I didn't want to buy one and then break it, lol. After using it, I have to imagine the people who broke theirs were not using it right because I had 0 issues. They must be using it for some heavy thick wall tubing it wasn't designed for or something. be careful though, it's possible to expand it too much and then the muffler never fits. I would go 1/4 turn and then check fit, another 1/4 then check fit, I think I only needed 3/4 of a turn for a really snug fit on the cat box.
    Ever tried. Ever failed. No matter. Try Again. Fail again. Fail better.
    - Samuel Beckett
    A tool is just an opportunity with a handle
    - Kevin Kelly

  9. #8
    Senior Member DesmoDog's Avatar
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    I've got an expander similar to the link but it's stepped so there are a couple different diameters to choose from. I've found it's most useful for making pipes round again as opposed to actually sizing anything, but I've also got access to industrial strength sizing machines, so I'm pretty lazy when it comes to manually doing that.

    As for people breaking those tools... yeah, it's hard to say how they were being used. Or what they were used on. I've broken manufacturing level tooling (operator error) so can't really blame anyone for being ignorant on how to use stuff. The guy in charge was happy I told him I broke it vs being pissed it was broken. Shit happens, I wasn't the first guy to do something stupid. I also once had a muffler built for a buddy that had an inlet slightly smaller than what he needed. When he brought it to the exhaust shop, they stuck it on their sizer and the machine stalled before the pipe size changed... yeah, it was a bit more stout than the average aftermarket part. I also suspect the guy had the sizer set into the muffler so he was trying to expand three layers of metal. Whatever. To be fair, the deeper the sizer is inserted the less chance there is of breaking anything. Apparently the shop owner handed the muffler back to him and asked where the hell he got it.
    -Craig
    The Mighty Monza Jr. Thread: https://www.caferacer.net/forum/proje...r-project.html

  10. #9
    Senior Member brad black's Avatar
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    i've had one of those for years. i don't think it's great for making things noticeably bigger, but it does help with roundness. we used to use it to make slip on mufflers actually slip on. from memory, staintunes used to be kind of crap at that at times.

    not sure what you'd have to do to break it. i put it in the pipe then hit it with the rattle gun. handles that no wuckers.
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  11. #10
    Senior Member DesmoDog's Avatar
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    Quote Originally Posted by brad black View Post
    i've had one of those for years. i don't think it's great for making things noticeably bigger, but it does help with roundness. we used to use it to make slip on mufflers actually slip on. from memory, staintunes used to be kind of crap at that at times.

    not sure what you'd have to do to break it. i put it in the pipe then hit it with the rattle gun. handles that no wuckers.

    Agreed.

    But the real reason I'm replying is to find out if "no wuckers" is an Aussie thing, or a typo?
    TrialsRider likes this.
    -Craig
    The Mighty Monza Jr. Thread: https://www.caferacer.net/forum/proje...r-project.html

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