Topic: CB550K1 mufflers - difference between 323 and 374

[Erny]

Is there any visible difference between mufflers 18xxx-323-060 and 18xxx-374-70x?

I mean different shape, stamp etc..whatever

Why I ask - I have 4 old stock 323 mufflers (all have corroded holes) and have 1 new 323 (SL). If I buy remaining 3 374s and combine them with 323 will it be visible or not?

Thanks

[seanbarney41]

yeah, they look totally different...374's are basic megaphone

[Erny]

Wau. Spare parts catalogue shows them as replacement... Strange, no?
Are 374s like on K3? Or similar like CB750K K7?

[seanbarney41]

Wau. Spare parts catalogue shows them as replacement... Strange, no?
Are 374s like on K3? Or similar like CB750K K7?

yep, very similar look as cb750 k7.  I wouldn't expect them to fit a k1 very well either as, I believe, there are changes to the footpegs and brake pedal

[TwoTired]

So, I looked in my Honda motorcycle identification guide.  Bear in mind this refers to US models.  Not sure what they did in Europe.

323 was the product code for the CB500 Four K0 and the K1.
The pipes were stamped 323 as this was where they were first used.
The Cb500 K2 had product code 197.  So, any part first used on that bike would have a 197 product code.  They had 323 stamped pipes, the same as previous models.
In 1974 the Cb550 was introduced with product code 374.  The exhaust remained the same as the CB500  and when I replaced mine, they came with 323 stamped on them along with additional EPA stamping the originals didn't have.  Clearly newer production.
The 374 product code remained for the 75 K1 and the 76 K2.  The pipes were still stamped 323 and were functionally the same as the CB500 pipes.

The F model Cb550s were Product code 390, with clearly different 4 into 1 exhaust systems.

1977 K3 model was product code 404 and had redesigned 4 to 4 exhaust.  Not strictly interchangeable with the prior 323 type.  (But, it has been done, forcefully).
The last model 404 was 1978 and used the same pipes as the 77 model.


I believe if you order 374 pipes, they will come stamped 323, work and fit the same as what it originally had.

Cheers,

[my name is nobody]

The 374's supercede the 323's, and are correct on the cb500/550k models thru the k2 ('76)
The k3 pipes are different, and are a major PIA to make work, although it can be done.
My replacements came from Honda with 374 part tags, but they're stamped 323

[my name is nobody]

TT ya beat me typing

[Erny]

Thanks guys, this is what I was looking for (as per spare parts catalogue)!

So will try to get some

Many thanks for clarification

[bryanj]

Original 323 do not have all the Federal verbiage rolled into the back face 374 do. Both fit identicaly.

[Little_Phil]

Thanks guys, this is what I was looking for (as per spare parts catalogue)!

So will try to get some

Many thanks for clarification

But 374s are rare and 323s rarer still. DSS/CMSNL  and others sell good reproductions, but they are unlikely to split a set unless they have some "seconds". These sets come with the EPA stampings on the back which is about 10 lines long. The are marked 323 not HM 323.

[TwoTired]

But 374s are rare and 323s rarer still. DSS/CMSNL  and others sell good reproductions, but they are unlikely to split a set unless they have some "seconds". These sets come with the EPA stampings on the back which is about 10 lines long. The are marked 323 not HM 323.

You actually found some stamped 374 from Honda?

[seanbarney41]

Wow, I really got this one wrong.  I was, of course, thinking the 374 pipe was 404...sorry for any confusion.

[Little_Phil]

But 374s are rare and 323s rarer still. DSS/CMSNL  and others sell good reproductions, but they are unlikely to split a set unless they have some "seconds". These sets come with the EPA stampings on the back which is about 10 lines long. The are marked 323 not HM 323.

You actually found some stamped 374 from Honda?

No the Honda 374s are stamped HM323 but have the EPA detail on the back. I also heard that later pipes were of thicker material after so many early failures on 323s on 500K0. Not sure this is true.

[bryanj]

The repros also dont have the extra markings(sl etc) that tell you where they go, as if you cant fogure it out. Yes the early US K0 had and extended muffler warrantee due to rot.

[Deltarider]

My CB500K2-ED originally came with -374- stamped mufflers. I remember that so well because when I scored NOS pipes (at a very low price) I discovered, to my dissappointment, they were not "100% identical". Mind you: the only difference being that stamped in number! I'm probably the only one that can testify this, but I'm backed by the CB500K2 (ED, F, G) parts list (cf p.59 in: http://www.honda4fun.com/pdf_parts_list/pdf_spac500/CB500-76/CB500-76_3.pdf). BTW, those mufflers were not the only -374- parts that that particular model CB500K2 (ED, F, G) (marketed in 1976 on the European continent) shared with the oldstyle CB550K models.

[Little_Phil]

I have a receipt from DSS dated 13 Jan 1995 for 18300-374-707 to 18450-374-707. They were £75 per exhaust +17.5% VAT, and were stamped 323.

[TwoTired]

I have a receipt from DSS dated 13 Jan 1995 for 18300-374-707 to 18450-374-707. They were £75 per exhaust +17.5% VAT, and were stamped 323.

Wow, Imagine that!  It's almost like you live in the real world?   

I bought my pipes 74 Cb550 pipes from a Honda dealer about the same time.  Yep, stamped 323.  Amazing, isn't it?

Cheers,

[Deltarider]

New or NOS?

[bryanj]

Honda were still manufacturing, or having them made, up until the late 90's