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1980 CX500 Custom
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Discussion Starter · #1 · (Edited)
Purchased an OEM muffler off Ebay for my 1980 CX500 Custom.
Has same part# (HM449462 HONDA, SANKEI 2049) as the rusted-out muffler since removed.
The od of the old muffler is 41mm and the recently purchased is 43mm.
Did these mufflers come with different od, even though same part number?
The od I'm referring to is the end that goes into the H-box collector.
I cleaned-up the inside of the collector, but the 43mm muffler not going in; may require
heating the collector area and a bit of "influence" with a rubber mallet.
I'm asking before end up damaging things...should I proceed, stop and not use new muffler, get some type of reducer, perhaps cut a couple of "slots" in the end of new muffler?
 

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1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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There should be a fiber gasket in there. They usually turn to stone and fuse to one side or the other. I suspect you need to clean the old gaskets out of the collector and get a new set.
 

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“They usually turn to stone . . .”
Best description I’ve heard yet regarding those aged seals. LOL
 
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Discussion Starter · #4 · (Edited)
Old gasket is out and in my hand...but, looks can be deceiving. Upon closer inspection a layer
of gasket seems to have turned to stone and fused itself to the inside surface of the collector.
Making progress with a small sanding drum. I'll have that muffler installed soon. Thanks for the advice; it was spot on !
 

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1981 GL500 Silver Wing
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Was wondering how this went for you 2 months after your initial post? I just got my pipes off (see pics) and will need to figure out new mufflers. I seem to have a similar gasket issue. One muffler seemed to come out with part of the gasket and the other with all of the gasket still in the collector. How big of a headache was it to grind these out? Any advice?
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1980 CX500 Custom
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Discussion Starter · #6 ·
Was wondering how this went for you 2 months after your initial post? I just got my pipes off (see pics) and will need to figure out new mufflers. I seem to have a similar gasket issue. One muffler seemed to come out with part of the gasket and the other with all of the gasket still in the collector. How big of a headache was it to grind these out? Any advice? View attachment 211473 View attachment 211474 View attachment 211475 View attachment 211476
I replaced left-side muffler with a good used part sourced from ebay. My originals were in much the same condition as yours. I used a Harbor Freight sanding drum kit to clean-up the id of the collector, but only to the point that replacement (with its gasket) would fit tight and with a little "influence" from a dead-blow hammer and wood block. It was quite the project; so much so that I decided to salvage my bike's right side muffler while still connected. I used JB Weld Tiger Patch kit to fix the rotted section of pipe near the collector clamp. That pipe must have had about a one inch hole and the kit worked great. Although for extra strength, I did place a "fernco" type plumbing clamp over the entire repair. The fernco(1-1/2"?) was sourced from Home Depot, made of stainless steel. is corrugated and actually looks cool. Of course, I only used the part after removing the rubber pipe connection portion. This was a great solution and fernco came with two clamps as well. The rear-end of that muffler was also getting quite rotten, but I was blessed with another low cost, effective solution....I used a small handheld kitchen-type strainer/sieve from Dollar Tree! I used the metal screen from the sieve and its near perfect diameter and being concave/convex fit well! Applied JB Weld to end of muffler and pressed the screen into that layer of epoxy. Let set up and cure then applied/spread another coat of epoxy over. I was impressed with the results. Salvaged the OEM part, looks decent, sounds MUCH better, bike runs as intended (backpressure). I really should share pics of these fixes.
 

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Was wondering how this went for you 2 months after your initial post? I just got my pipes off (see pics) and will need to figure out new mufflers. I seem to have a similar gasket issue. One muffler seemed to come out with part of the gasket and the other with all of the gasket still in the collector. How big of a headache was it to grind these out? Any advice?
You may want to cut a thin slot with a Dremel wheel on the muffler side and try to pry off the gasket. Yes, they get hard, but it should work in the exposed sides. I would also try something similar on the interior portion with a cold chisel or old screwdriver and mallet.
 

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I'm trying to get a pair of headers to let go of the h-box. Lot's of propane and mallet. Tried spreading the flanges. Nothing's worked so far. I recently picked up a MAPP torch for another project. Might need to try extreme heat next.
 

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I find exhaust disassembly to be one of the most unpleasant tasks on these aged machines. Fortunately the mufflers are usually shot before I start, because they certainly are by the time I get them off. Chisels, cut off wheels, ugh! I’m very open to some new tricks here.
 
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1981 GL500 Silver Wing
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I'm trying to get a pair of headers to let go of the h-box. Lot's of propane and mallet. Tried spreading the flanges. Nothing's worked so far. I recently picked up a MAPP torch for another project. Might need to try extreme heat next.
I used propane and torched the collector box an inch below where the muffler meets the box. I heated until the collector box turned orange. Then I used a hammer and wood block against the bracket on the muffler. Popped off pretty easy when it is that hot.
 

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1980 CX500 Custom
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Discussion Starter · #11 ·
I'm trying to get a pair of headers to let go of the h-box. Lot's of propane and mallet. Tried spreading the flanges. Nothing's worked so far. I recently picked up a MAPP torch for another project. Might need to try extreme heat next.
MAPP gas is your friend for stubborn things like exhaust components
 

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1981 GL500 Silver Wing
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Wondering if anyone has put a set of Emgo mufflers (any model) on their bike and would be willing to share a pic? Looking at original mufflers on Ebay and slim pickings for anything good.
 
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