CL77 Exhaust/Silencer Question

[Dick Steinkamp]

I've hunted for an answer, but no luck. It just might be my lack of search expertise. Sorry if this has already been addressed.

My 1966 CL77 came to me with (broken) silencers in the exhaust pipes and no muffler (The picture is of new silencers)...

s-l1600.jpg

The owner's manual I have (the common PDF one which i think is 1965) shows how to service these silencers...

Screen Shot 2022-11-07 at 12.48.00 PM.png

....but it also pictures the bike with a muffler...

Screen Shot 2022-11-07 at 1.00.56 PM.png

The parts book I have (Nov 66), only shows the muffler, no silencers...

Screen Shot 2022-11-07 at 12.49.25 PM.png


1. Was there a SN when the CL77 changed from silencers to a muffler?
2. Did some CL77s come with BOTH silencers and a muffler?
3. I see David Silver has the repoped mufflers but I can't find the packing (#9 in the illustration 18391-277-010). Is there a source?
4. Is there a source for the silencers? I see one in Indonesia, any in the US?

Thanks!

[66Sprint]

CL72.png

Pic is for CL72, IIRC, the CL77 diffusers were different.....

[Dick Steinkamp]

So, did CL72s have both? Or one or the other? If one or the other, any idea of the SN changeover?

[66Sprint]

IIRC, muffler or internal diffusers, not both.....Bill Silver will have the correct answers.....

[ancientdad]

Moved to 250/305 Exhaust section.

[ballbearian]

Your first pic of new baffles are for CA/CB, I think. Got no idea if baffles in "the guppy" muffler on the CL's. Doesn't look like it in the parts diagram.

Just noticed the baffles in the pipes (they are different). I'd guess most got tossed and the guppy too, in favor of Snuf-or-nots.

[MrHonda1948]

Dick, Here is a copy of the part numbers from the parts books, circa 1973.

1. Was there a SN when the CL77 changed from silencers to a muffler? All the CL77s came with the slip-on muffler in the beginning. The baffles used a headless screw that inserted into the nutplate of the baffles. This allowed the muffler packing to be slid over the screws without damage.
2. Did some CL77s come with BOTH silencers and a muffler? Yes, early ones.

CL72 exhaust 1.jpgCL72 exhaust 2.jpg





3. I see David Silver has the re-poped mufflers but I can't find the packing (#9 in the illustration 18391-277-010). Is there a source? Unknown at this time.

4. Is there a source for the silencers? I see one in Indonesia, any in the US? Haven't seen any for awhile... FYI an image of the later 277 code baffles. https://www.nospartsnow.com/nos-honda-cl72-exhaust-pipe-diffuser-baffle-18311-277-000/


I have about 1500 pages of CL specific info available via digital download. See www.vintagehonda.com for details.

Bill Silver

[Dick Steinkamp]

Thanks, Bill

I did get your digital download on the CL77 last week. Great info and it's been a big help already.

I'm still a little confused (not uncommon for me). In the parts manual pages you sent, there are two baffle PNs listed. One is for use with the muffler (277), the other (273) then must be for use without the muffler? Were there some CL77s delivered without the muffler and only the 273 baffles?

[MrHonda1948]

CL77s only came with slip-on mufflers and the 277 baffles. They did not come with 273 baffles and no mufflers. A lot of owner's removed the muffler and some replaced the 277 baffles with 273 as they were less restrictive.

[Dick Steinkamp]

Got it, Bill. Thanks again!

[bilbikek411]

I had a 1966 CL77 305 as my first good 'street bike' when I was 17 on a learner's permit.
The bike had no baffles,etc. so I purchase an OEM pair of baffles which definitely helped;I later purchased the 2into1 OEM slip-on muffler which had the rubber seal(I was shocked that rubber didn't burn-up with the exhaust heat)and installed it with both inner baffles and it made a wonderful difference with a quiet ride.I didn't know the bike could be that quiet ;this all happened between 1974-75' when parts were readily available.
I did use the inner baffles that didn't show from the outside,when you looked at the exhaust pipes from the seat downward.I remember needing to switch from standard 6mm baffle hold-down screws to the headless ones so that I could slide the outer chrome 2into1 muffler with rubber gasket over those pipes.

[Dick Steinkamp]

I had a 1966 CL77 305 as my first good 'street bike' when I was 17 on a learner's permit.
The bike had no baffles,etc. so I purchase an OEM pair of baffles which definitely helped;I later purchased the 2into1 OEM slip-on muffler which had the rubber seal(I was shocked that rubber didn't burn-up with the exhaust heat)and installed it with both inner baffles and it made a wonderful difference with a quiet ride.I didn't know the bike could be that quiet ;this all happened between 1974-75' when parts were readily available.
I did use the inner baffles that didn't show from the outside,when you looked at the exhaust pipes from the seat downward.I remember needing to switch from standard 6mm baffle hold-down screws to the headless ones so that I could slide the outer chrome 2into1 muffler with rubber gasket over those pipes.

It's that rubber seal/connector that appears to be rare today. PN 18391-277-010....Packing). The muffler is repoped, but without that connector piece it can't be used

packing-muffler-nas_medium18391277010-01_5615.jpg

[bilbikek411]

I would hunt-around for that OEM rubber "packing" and not settle for a repop on that part;somehow they made the rubber good enough to resist heat.

[MrHonda1948]

I would hunt-around for that OEM rubber "packing" and not settle for a repop on that part; somehow they made the rubber good enough to resist heat.

The packing was made of a silicone rubber that handles high heat. Similar packing material was used on the CB/CA mufflers that had an o-ring inlet on their mufflers which were much closer to the engine heat than the mufflers on a CL. I don't think anyone would re-pop them using a regular rubber product.

Bill Silver

[Dick Steinkamp]

I eMailed David Silver who sells (makes?) the reproduction muffler. They sell their PN 18392MK4000 which is a reproduction of 18391-317-010 to replace the NLA 18391-277-010. Two are required. $8 USD each. They look like this...

18392MK4000_large.jpg

[MrHonda1948]

Those are not going to work for the early style muffler. That is a packing for the late model exhaust with the welded on muffler and it seals the lower pipe to the muffler on that version.

[Dick Steinkamp]

OK...Thanks, Bill!

When you say "early" vs "late", what is the serial number break?