Exhaust choice


CBX1000chris
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Re: Exhaust choice

Post by CBX1000chris »

Thank you for the replies.
I currently have the original left exhaust back on the bike and the side stand folds up bang in the middle of the oblong bracket rubber so the side stand would seem to be straight (unless the exhaust wasn't' where it should be but it has no damage suggesting it's been bashed).
My original system definitely has brackets for one round (centre stand) and one oblong (side stand) rubber stops. The stamping on the exhaust is Sankei 2040 and HM422 so different to the brackets you've seen Dave. My bike is a '79 North American spec. model.
Cheers,
Chris.

CBX1000chris
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Re: Exhaust choice

Post by CBX1000chris »

Dave - I decided to have a quick look at the CMS website and the parts lists for the different CBX models and could see the design of the side stand rubber changed for the later 'B' models. I guess my bike could have a later model exhaust but it doesn't have the link pipe and is definitely stamped HM422?

jnnngs
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Re: Exhaust choice

Post by jnnngs »

Chris,

A few comments.
1. no idea why they decided to number the exhausts differently, strange thing to do as a you say.
2. CMSNL supply the exhausts to David Silver. No need to cover the logo up!
3. I suspect your exhausts gaskets are the thick variety. In which case the studs aren't quite long enough
4. when fitting the left exhaust make sure it is lined up in the headers correctly. That would cause the issue you are seeing. You may need to "adjust" the headers so they fit better - make the gap between 1 and 3 wider / closer.

overall, I was not impressed with the quality of these latest replicas. The set I had did fit OK - eventually.

Paul.

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Re: Exhaust choice

Post by jnnngs »

also, I have seen Z model exhausts with both the rectangular rubber and the two circular ones, maybe different design for different markets.

jnnngs
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Re: Exhaust choice

Post by jnnngs »

Final comments!
on the set I fitted, they didn't fit very well on the bike when it arrived with me, turned out the centre downpipes were in the wrong sides - who ever fitted them didn't spot the numbering change. Worth checking you got yours in the right sides.

I think you said your existing exhausts had the EPA emissions statement on them - in which case not original, but later honda replacements, would explain the change in rubber stops.

CBX1000chris
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Re: Exhaust choice

Post by CBX1000chris »

Thank you everyone. To be clear, I fully accept I may be missing something and be completely in the wrong!

However, for information I thought I'd post close up pictures of the stand rubber bump stop brackets.

20220213_174621_1.jpg
20220213_174628_1.jpg

You can clearly see the difference between the alignment of the brackets. This is why my side stand completely misses the bump stop and hits the silencer on the pattern part but aligns perfectly with the bump stop on the OEM part. It would be fantastic if someone could check their rubber bump stop bracket position and let me know if theirs is the same and if the side stand aligns correctly. If David Silver tells me my side stand is bent I'll have to say this can't be the case because everything aligns correctly with the OEM part.
The other disappointing thing is the position of the 'dinks' deliberately put into the silencer for the centre stand lever end clearance. Look at the two pictures above and the one below. If you go to the trouble of making the dinks they ought to be in the correct place!

20220213_180727_1.jpg

Paul - thank you for the suggestion re. gasket thickness, I didn't know there were different types. Do you know where I can buy skinny gaskets?

Thank you all for your input.
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JoeInTUS
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Re: Exhaust choice

Post by JoeInTUS »

Chris

Here's a photo of the bump stop brackets on another reproduction exhaust (edit: this is a David Silver exhaust produced 6-8 years ago) arrangement looks similar to your exhaust and does not have the offset like the rectangular sidestand stop.
20220215_113446_001.jpg
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Joe S
Tucson, AZ

daves79x
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Re: Exhaust choice

Post by daves79x »

Yes, 'paragraph' 422 replacement pipes from Honda have the later rectangular side stand stopper.

Dave

CBX1000chris
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Re: Exhaust choice

Post by CBX1000chris »

Thank you everyone for you contributions to this thread, most helpful. I decided I needed to have a closer look at my side stand and found this thread:

viewtopic.php?f=27&t=7484

Once I removed the side stand I could see quite clearly it was bent and by chance (or design - read bending to suit) the side stand was folding up directly onto the rubber on my old silencer. Once I straightened the stand it was a much closer match to the rubber on the DSS silencer. I think this might be the first time I have found an example to two wrongs making a right! I straightened the stand in my hydraulic press. I bought the press last year specifically to rebuild the crankshaft on a 1966 BMW R27 I was restoring and didn't expect to use it ever again. Yet another tool in the garage I wonder how I ever managed without, no longer using the vice as a press (or a hammer and hope!).

The mounting bracket studs on the DSS silencer were very close to the swingarm but when I tried the bracket off my old silencer the clearance was OK. When side by side the two bends in the brackets look to be the same but there must be a small difference.

The difference in height of the two silencers when viewed from the back of the bike, about 20mm, was resolved by lifting the left silencer while tightening the bolts and pressing down on the right silencer while tightening the bolts.

I managed to get the clamp on the no. 2 exhaust pipe to tighten better by loosening it right off and tightening it again, perhaps the clamp wasn't seated correctly first time?

This only leaves the issue of the available thread on the exhaust studs. I have the 'fibre' type gaskets fitted so I think I'll order a set of the copper gaskets and see if they crush up better.

So, thank you again to those who helped and maybe this thread will offer some help to the next person to struggle with the job!

20220216_175253_1.jpg
20220216_175227_1.jpg
and the little Beemer

20210705_160618_1.jpg

Kind regards,
Chris.
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daves79x
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Re: Exhaust choice

Post by daves79x »

Indeed! Old BMWs and CBXs go perfectly together.

Dave

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NobleHops
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Re: Exhaust choice

Post by NobleHops »

Haha! I'm glad that old thread came in handy! We have a press now too and that's a better way to do this for sure. And BTW thank you for closing the loop on your struggles, that contributed a lot more to the future knowledge base on troubleshooting this installation process.
Nils Menten
Tucson, Arizona, USA '80 CBX, sort-of restored :-)

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