Topic: CB500/550 Mufflers - Are these NOS or Repop?

[34barab]

A future project will be trying to restore a CB500 or 550 to as close as possible to factory.  No room right now and no time frame yet.  Came across a set of stamped HMCB500 HM323 mufflers that look like NOS.  I'm no expert so I'm hoping more knowledgeable forum members will offer opinions, comments, etc.  Pictures attached, and I can post more specific ones. 

Thanks
John

[34barab]

Four more pics

[bryanj]

Those marking make them original Honda for the 550, hence all the verbiage on the back but are direct replacements for the 500 and are what Honda supplied for both

[Scott S]

 Very nice. There are a few brackets and rubber connectors you'll need , too.

[Deltarider]

Congrats, they're the real thing, although they may be repro's. Doesn't matter, I heard good things about them. Tip: avoid short rides and they'll last a long, long time*. Where did you get them?
* My first set lasted between 75.000 and 80.000 kms. I seem to remember that the first original set on my CB500K2-ED, a model that was assembled in 1976 and that shared parts with the CB550K2, had -374- as middle number. My second set I bought new, but real cheap. Here's how. Mid 80s several dealers had them still lying around, because in the 70s many that bought a new CB500, ordered the dealer to replace the original 4-4 by some 4-1. This before the bike had run even one mile. Can you believe it?

[JamesH]

They are definitely genuine Honda HM323 pipes there (but later / more recent manufacture). Definitely worth having for your restoration. NLA from Honda for 3/4 years now...


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[34barab]

So...… Looks like Christmas came early this year.   Thanks Santa!!   I was hoping they were real.  Found them on CL, had only been listed a day.  The middle part code on these is 374.  It's gratifying to finally get one right after so many  mistakes since I got interested in old Hondas.  Thank you all for your feedback.  John   

[bryanj]

Yup 374 is for 550/4 whìlst 323 is 500/4, i picked up a very good nos gas tank cheap because it had a 374 number and was an "odd" colour------- Boss Maroon Metallic

[MikeSimon]

The "EPA stamps", I think are 1983 or later.

[bryanj]

I thought 75 onwards, same as US always had vin plates with build date shown for appropriate rules whilst UK didnt get them till i think 77

[Gene]

Those look great. nice find.

[Deltarider]

The middle part code on these is 374.

Thanks for that info, although the pics you posted (451 and 452) showing -323-, seem to contradict what you say. I hoped I had confirmation I had remembered well that I also had the -374- number on my CB500K2-ED mufflers. I can't recall mine had the EPA text however. When you are to fit them, look here for how to do it: http://forums.sohc4.net/index.php/topic,82323.msg925422.html#msg925422new For a correct mount it is important to have a brackettop positioned at each side of the frame eye. I also recommend to have cushions on the floor whenever you mount/dismount them, so if they drop, they won't come down hard. If you don't, the inner damper may come loose, the more when they're old after years of use. Don't ask me how I know.

[bryanj]

The stamped number was always 323 but the sold under part number changed to 374

[Deltarider]

The stamped number was always 323 but the sold under part number changed to 374

Then, how in the world is it possible that I remember I had the number -374- on mine? Mind you, this was long before I knew about any other CB550Ks, the ones that had not been imported in Europe. At the time I didn't even know the models CB550K, CB550K1 and CB550K2 had existed. I was conscious however of the number -323- indicating the CB500. I remember distinctly: hey, that's strange, what is that number -374- doing on my mufflers as I am supposed to have a '323' bike? And in those days I had never seen any part list...
Another thing. Maybe I have a clue why the muffler partnumbers were changed from xxxxx-374-700 into xxxxx-374-707. Could it have to do with that EPA text that the former mufflers did not have?

[34barab]

i think the last three digits of the Honda part codes indicated a vendor change.  Here is a link to one explanation of Honda's part codes.

https://www.kaila.net/tl125/tl125partcode.html#productcode

Also, I got beat up Honda boxes with them that still had labeling tags with "374" as the middle three digits of the part codes.  Being a "doubting Thomas", the boxes didn't prove anything to me.  (I think some sellers use packaging to sell fake items.)

Deltarider, thanks for the how-to.  John

[bryanj]

The 500/550K3 had 4 into 4 but a different design with a different middle number. All the "trumpet" type silencers i have seen had 323 on them.

[Deltarider]

https://www.kaila.net/tl125/tl125partcode.html#productcode

That list is another example how things on the internet can look official and yet have errors.
For example: the CB500 K0/K1 did not have '232' as productcode but 323.

Deltarider, thanks for the how-to.  John

Thank Sohron instead. Thanks to him I found out I had wrongly positioned my brackets. As you can see in the pictures below (shot at a dealer's workshop), even professionals do not always do it right when they fit new repro exhausts for their customers. Feel free to contact me when you are about to begin. I have some more info and pics concerning the brackets and solutions for possibly damaged 6mm studs.

[Deltarider]

The 500/550K3 had 4 into 4 but a different design with a different middle number. All the "trumpet" type silencers i have seen had 323 on them.

I am aware of that. The question is: how many model CB500s* and CB550s** that were not imported in the UK have you seen and then in the original state... Only an owner of my type or a CB550K-K2 that is dead sure his still has the original exhausts could answer the question. Not much chance, I'm afraid.
*CB500K2 (ED, F, G), marketed on the European continent in 1976-7
** CB550K, CB550K1 and CB550K2 not marketed in Europe at all.

[Can550]

Nice stuff
If you don’t have and need stock mounting brackets, let me know. Not NOS but not far from.
Cheers


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[bryanj]

I have had several"imports" through my hands with remains of original exhausts and have all the honda parts books. The K3 came to UK  and Europe in late 76 as a77 model year bike with the 500k3 at the same time in some European countries. I remember the Honda dealer i worked for at the time of the 550k3 trying to get 500's for customers and not being able to.

[Deltarider]

OK, once more. It was only after I had gathered 4 NOS exhausts for my CB500 that one thing struck me immediately when I compared them to the ones I had on my bike, knowing the exhausts that I was to abandon. These NOS exhausts I had scored all 4 had the number HM323, where the original set on my CB500K2-ED had HM374. At the time I concluded that the 323s I had bought NOS, originally came from older models CB500s (knowing CB500 and CB500K1) than my 500 which was assembled much later, probably in 1976.
BTW, not trying to be stubborn, but the K3s have nothing to do with it. They had much different silencers.
Maybe I am the only one who consciously has witnessed this. Folks that say this can't be true, can maybe answer why the exhausts in the CB550, CB550K1, CB550K2 parts list have middle number -374- in spite of being identical to the ones on the CB500 as many state. I know the following is not a 100% proof for folks that question my observation back then, but one can not deny there are lots and lots of other parts in that CB550 parts list that still carry the -323- middle number. So why was the exhausts middle number changed? My observation then has always kept hanging in my memory and it is not the first time I have mentioned this oddity here.   

[TwoTired]

All my cb550k mufflers are stamped 323, including the new set I bought from Honda parts department. Those had the added EPA compliance stamping.

The 78, of course, has different mufflers.

[Deltarider]

Yes and all your plugcaps read 10kΩ... also bought through the Honda parts department...
Can you believe that until now I never knew you had these silencers, let alone that you actually bought them through the Honda parts department...? Wow! You really surprise me, TT. Who ever had expected that? I mean, it is so unlike you, you and your 'economic' Unifoam airfilter elements... Anyway thanks for clearing things up... if that is what you did...
OK, the mystery remains. Mine were stamped HM374. It was the first thing I noticed when I compared the fresh bought NOS with the ones then still on my bike. Mind you, at the time I had never seen a Honda parts list. I did not even know they existed (I knew dealers had fiches). Also at the time I was not aware the US had had K-models in between the CB500 and the CB550K3. Models like the CB550, K1 and K2 were not imported in Europe and I did not know of their existence. I had a vague notion the 323 number was somehow related to the CB500. But that HM374 on my silencers... I had no clue. I did not even know it was a product code like 323. The only thing I do know is that I noticed this difference in stamped in number.
The good thing is, I was never tempted to state this and that is law. Some of you may remember I've reported this not having 323 but 374 stamped on my old silencers more than once (also in the UK forum*) and that I have inquired if I was the only one or if others had had the same. Looks like I was the only one.
Ok, here's another puzzle for those of you that like to solve them and to share knowledge: any idea why the middle numbers of the four exhaust brackets differ? Have a look here at the last page of:
http://www.honda4fun.com/pdf_parts_list/pdf_spac550/CB550-K0-K1-K2/CB550-K0-K1-K2_06.pdf Again 323 and 374... Why would Honda have given them different middle numbers? Odd isn't it? 
*http://www.sohc.co.uk/index.php/topic,9693.msg68455.html#msg68455

[TwoTired]

... I had no clue. ...

This is the most truthful and relevant post you've ever made.

Bring that into present and future tense for a universal truth about 99% of your preaching, pulpit banging, alternate reality posts more apt to mislead than to help anyone else but yourself.

You go ahead and carry on the Pecos Bill style storytelling.  (Like you could actually stop, ha ha.)

Regarding your imaginative mystery.  Here's another for you to consider.  How do you keep a blithering idiot in suspense?

[Scott S]

 Rule #5, guys.

 Feel like trading insults, be my guest, but take it to PM.

http://forums.sohc4.net/index.php/topic,55941.0.html