Possible to adapt later exhaust to earlier head?

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998cc

998cc

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Good day folks. My bike is a 74 model produced in September of 73. I ordered and received what I thought was the correct set of exhaust header pipes, but they are the later version. Is it possible/practical to adapt these to my Commando, or do I need to send them back for the correct set?

Thanks.

~998cc
 
I no expert but I think so. In the not too distant future I will be going the other way. 750"S" system on a 850 MKII
 
Here are a couple of photos.

The new unbalanced pipe.
Possible to adapt later exhaust to earlier head?


The existing balanced pipe has a conical flange.
Possible to adapt later exhaust to earlier head?


~998cc
 
Seem to recall I did this back in the late 70's when parts were scarce. 850 balanced system onto 750 engine, recall split collets at the head end of the pipes, locked in by the threaded retainers as per 750 system. Don't blame me if I'm wrong.
Cheers, Martin
 
Thanks L.A.B. for the link to the earlier thread. From the info in the thread, the AN website, and comparing to what is installed on my Commando, it looks like my exhaust is Mk-III, but the hardware it was installed with is incorrect for the pipe flange. Flat sealing washers (not conical) were found. See photo:
Possible to adapt later exhaust to earlier head?

It looks as if the new pipes I have may be correct for the bike and will work with the existing hardware--collets and short nuts (the thread depth of the nut measures +- .575"). Can anyone provide some insight on this and possible differences in pipe bends downstream?

~998cc
 
998cc said:
From the info in the thread, the AN website, and comparing to what is installed on my Commando, it looks like my exhaust is Mk-III,but the hardware it was installed with is incorrect for the pipe flange. Flat sealing washers (not conical) were found.
Click to expand...

Often referred to as 'Mk3' pipes but also listed in the Mk2/2A supplement for the Mk2A.


998cc said:
It looks as if the new pipes I have may be correct for the bike and will work with the existing hardware--collets and short nuts (the thread depth of the nut measures +- .575").
Click to expand...

Yes.
 
Fullauto said:
I thought all 850s came with the balanced pipe. In fact, I'm sure of it.
Click to expand...


I wasn't saying unbalanced pipes are, or were, "correct".

998cc said: "It looks as if the new pipes I have may be correct for the bike and will work with the existing hardware--collets and short nuts (the thread depth of the nut measures +- .575")."

So "correct" in the sense that the new pipes will work with the existing hardware and why I replied "Yes".
 
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Gentlemen.
Whatever the case, I appreciate the sharing of your knowledge in helping this longtime Norton aficionado (with little Norton mechanical experience) avoid making the mistake of sending back the technically correctly fitting (though non-balanced) pipes and then ordering the technically wrong ones for the hardware.

Sincerely,

Russ
~998cc
 
If you disregard the different performance aspects of different diameters, balanced or no etc., you can swap just about any Commando pipes for any others with the proper small parts. Some of the rosettes have less thread and length than others depending upon the sealing system (collets, crush washers and/or conicals). Balanced pipes need split collets or there would be no way to get the rosettes on.
 
Danno said:
If you disregard the different performance aspects of different diameters, balanced or no etc., you can swap just about any Commando pipes for any others with the proper small parts. Some of the rosettes have less thread and length than others depending upon the sealing system (collets, crush washers and/or conicals). Balanced pipes need split collets or there would be no way to get the rosettes on.
Click to expand...

Thanks Danno. Yes, that is becoming apparent! :) Interestingly, the new unbalanced pipes require the collets to be used. No worries though; it will be a better installation than what was just removed from the bike.

The learning continues. :)

~998cc
 
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