Repacking a 1975 GL1000 Muffler


Information and questions on GL1000 Goldwings (1975-1979)
Post Reply
NewGWguy
Posts: 5
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.








User avatar
Maz
Posts: 796
Joined: Tue May 19, 2015 4:43 am
Location: Kent, UK
Motorcycle: 1975 GL1000K1
1976 CB500T
1979 CB750L
1990 Yamaha FJ1200
1993 Suzuki GS500E

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
Ironically, Common Sense is the LEAST common of all senses!
User avatar
DenverWinger
Posts: 1831
Joined: Thu Jun 23, 2011 2:20 pm
Location: Denver, CO
Motorcycle: (s)
1980 GL1100 STD Vetter (2005-)
1993 GL1500 Aspencade (2017-)
1983 Trav-Lite Camper (2010-)
Past rides
1972 CL350 (1980-1988) sold
1978 Suzuki GS550 (1985-2005) sold
1977 GL1000 (2002-2006) sold

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
♫ 99 Little Bugs in the Code, ♪
♪ 99 Bugs in the Code. ♫ :(
♫ Take one down, Patch it around, ♪
♫ 127 Little Bugs in the Code. ♫ ♪ :shock:

~Mark
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.
User avatar
GL1000K1dan
Posts: 34
Joined: Thu Aug 09, 2018 3:26 am
Location: England
Motorcycle: 1976 GL1000 K1

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.
gc33
Posts: 28
Joined: Sun Sep 29, 2019 5:13 pm
Location: Perth Western australia
Motorcycle: 1981 Gl1100 naked.

Re: Repacking a 1975 GL1000 Muffler

Post by gc33 »

The company in UK.. Nhc panels is no longer.. Closed its doors about a year or so back. It's a shame but I guess there is a limited market for them. And even more tight arses that don't want to pay for quality yet whinge about the quality and services from certain online shops...
I would've like to know where their moulds went for that system tho....
Im trying to find someone here in Australia that would press out the 2 halves... I have a donor exhaust if I find someone...
User avatar
offcenter
Posts: 816
Joined: Sat Sep 22, 2012 2:10 pm
Location: Lake Hopatcong, New Jersey
Motorcycle: 99 Gl-1500 SE
76 GL-1000
77 Honda Trail 90

Re: Repacking a 1975 GL1000 Muffler

Post by offcenter »

DenverWinger wrote: Wed Dec 30, 2020 5:08 pm 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.
I was just about to say the same thing.
George in Jersey.
99 Goldwing GL-1500 SE
76 Goldwing Gl-1000
77 Honda CT-90 "Trail 90"
Winger1957
Posts: 35
Joined: Tue Oct 13, 2020 3:47 pm
Location: San Antonio TX
Motorcycle: 1978 GL1000

Re: Repacking a 1975 GL1000 Muffler

Post by Winger1957 »

Maz wrote: Wed Dec 30, 2020 4:01 pm 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
They do not make and sell that muffler any more. I tried to buy one and they said "sorry'.


Post Reply