Repacking a 1975 GL1000 Muffler


Information and questions on GL1000 Goldwings (1975-1979)
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NewGWguy
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Joined: Thu Oct 10, 2019 7:34 pm
Location: Oregon, United States
Motorcycle: 1975 GL1000 (Frame Off Restoration Underway)

Repacking a 1975 GL1000 Muffler

Post by NewGWguy »



Hi all,

Does anyone know where to install muffler packing in a 1975 muffler? Here is what I do know - The outlets on each side contain a removable perforated cylindrical baffle. Originally the baffle was packed with a rockwool type material (state of the art in 1975).

I purchased a very used original muffler. When I opened the two halves of the shell, I found loose rockwool in the chambers near the inlet. I'm not certain if there is supposed to be packing in this areas or not.

Question: Other than the perforated discharge baffles, should I install packing material in any other chamber of the muffler?

Here what I found when I split the top and bottom halves of my very used muffler.








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Maz
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Re: Repacking a 1975 GL1000 Muffler

Post by Maz »

It might be worth emailing the company in the UK that makes fantastic reproduction GL1000 exhausts - NHC Panels ltd. I think they distribute them in the US via a company called Sirius inc. The details are on Randakks site, though.
Maz
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DenverWinger
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Re: Repacking a 1975 GL1000 Muffler

Post by DenverWinger »

To be honest, that "Packing" looks to me like "Mr. & Mrs. Mouse" were raising the Mouse family in there. I don't think that belongs in there, if you test it with a match it probably burns.

Interesting to see the inside of the GL1000 muffler, now I can see why the GL1000 I had was so much quieter than my 1100.... :D
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NewGWguy
Posts: 5
Joined: Thu Oct 10, 2019 7:34 pm
Location: Oregon, United States
Motorcycle: 1975 GL1000 (Frame Off Restoration Underway)

Re: Repacking a 1975 GL1000 Muffler

Post by NewGWguy »

Thanks for your reply

Now that you say that, it seems very logical that my muffler turned into a mouse B&B. It also explains the loose wool type material and how it was placed so far upstream of the exhaust flow. If this is the case, then the only packing material in the '75 muffler must be the missing fiberglass mat surrounding the removable baffles.
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GL1000K1dan
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Re: Repacking a 1975 GL1000 Muffler

Post by GL1000K1dan »

Hi NewGWguy

It's good to see the internals of the silencer so thanks for posting the pictures.

Out of interest, how did you open it up and how were you intending to close it up ?
NewGWguy
Posts: 5
Joined: Thu Oct 10, 2019 7:34 pm
Location: Oregon, United States
Motorcycle: 1975 GL1000 (Frame Off Restoration Underway)

Re: Repacking a 1975 GL1000 Muffler

Post by NewGWguy »

I covered this in a little more detail in a parallel posting on the Reference Information forum. In a nutshell, the two halves are welded together with a thin bead around the perimeter of the housing. The weld is at the outer edge of a "lip" in the upper and lower half. A handheld grinder makes short work of removing the bead and leaving sufficient lip to reattach. The housing is reassembled by lining up the lips on each half and welding a new bead along the perimeter. It is clearly a labor of love as the rewelding and patching rust holes from the inside will take a bit of time.

I have already purchased the recommended Harley-Davidson replacement mufflers. Mostly, I was curious what the inside of the '75 - '76 mufflers looked like.


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