Exhaust with Two Crush Washers?

If you want a decent Exhaust rose nut..... http://seager-engineering.com/ or https://www.facebook.com/seagerengineering/

www.ebay.co.uk

NORTON 750 850 COMMANDO TWIN ROSE NUTS WITH SPANNER | eBay

ALLOY SPANNER. These are CNC machined from stainless steel bar to mimic as close to the original styling as possible, this has also allowed us to create a spanner which will allow precision tightning without damaging the finning.
www.ebay.co.uk

He has just made a batch and I received my new set this week.

I have a pair on the bike I have used since 2014/15 on a Fullauto head.

I fancy a new exhaust.....without silencing!

(been watching this guy's reels https://www.facebook.com/RaysonsUK https://www.instagram.com/raysons_exhausts/ Great for a bit of old school sand filled pipe forming)

Might never happen, but the existing exhaust would have to be cut to get the nuts off of it!
 
johnm said:
Just use what you need. No issue if there are two or whatever is required to tighten the exhaust properly.

It's interesting how in the old days we use to smooth out inlet and exhaust tracts to a polished surface but now people engineer in reverse cones and stepped headers to control reversion. Look at the exhaust ports of the new Fullauto type cylinder heads.

The most important thing is no leaks.
Click to expand...
D Ports as done by Mez. Not sure how far back they date, possibly even 1970s, also done with bathtub combustion chambers.

Second pic is Australian made Fullauto bought via Mick Hemmings in 2014.

Exhaust with Two Crush Washers?


Exhaust with Two Crush Washers?
 
Fast Eddie said:
You got a pic of the Mez combustion chamber Steve ?
Click to expand...
I do, though the link that Pierre-Francois (marinatlas) has included will get you more info about Mez' work.

I understood Mez did work for Mick Hemmings, though Mick never mentioned that to me. I am pretty sure that is why there is a pic of Mick's Commando on the Mez website Norton section. I am also pretty sure he actually did some reclamation on my short stroke head after I dropped a valve in about '77 or '78.

I think I am correct in saying that John, (Seeley920) actually has a bathtub head. I am also pretty sure he told me that the major issue was setting up the carburation, to the point that he put it to one side! My assumption is that although you get lots of compression, you lose flow/swirl/burn patterns around the chamber.

1702744396178.jpeg


1702744427221.jpeg
 
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Gone a bit far away from crush washers, sorry Jim!

This pic is a modified exhaust port, and it just uses one standard crush washer for sealing! This design was developed for the works monocoque/space fame installation, where there wasn't a lot of room for your rose nut spanner! I had one of these once! (1975 to 1980) Side fins also machined off a bit on mine so I'm pretty sure it was intended for a space frame.

1702745681135.jpeg
 
SteveA said:
I do, though the link that Pierre-Francois (marinatlas) has included will get you more info about Mez' work.

I understood Mez did work for Mick Hemmings, though Mick never mentioned that to me. I am pretty sure that is why there is a pic of Mick's Commando on the Mez website Norton section. I am also pretty sure he actually did some reclamation on my short stroke head after I dropped a valve in about '77 or '78.

I think I am correct in saying that John, (Seeley920) actually has a bathtub head. I am also pretty sure he told me that the major issue was setting up the carburation, to the point that he put it to one side! My assumption is that although you get lots of compression, you lose flow/swirl/burn patterns around the chamber.

View attachment 111568

View attachment 111569
Click to expand...
That looks very good to me, interest about the carburation and swirl tho…
 
Jdub said:
Hi to all, reviving this thread with a question: I am using standard 850 rose nuts with the Emgo non-balanced header set. Fully tightened, without any washer, there is rocking and room. With a single washer, slightly tighter, but with two I think I can tighten fully. So:

= I assume two washers, flat sides back to back, dome side one towards head, one towards pipe, for maximum seal?
= Has anyone introduced RTV hi-temp coating on these washers? Would that help the seal?
= Where may I purchase half-width rubber supports 06-0622 to tuck my exhaust pipe closer to the mounting / Z plate? I have searched RGM and elsewhere but no luck

Thank you for your replies!
Click to expand...
I have the Emgo headers and originally put them on with no washers but found out that the timing side pipe kept coming loose.Put one crush washer on both sides and no problems whatsoever since. I also use the hi-temp RTV sealant on the roses.
Mike
 
Fast Eddie said:
That looks very good to me, interest about the carburation and swirl tho…
Click to expand...
The hemi chamber shape has no squish and generaly needs more timing advance (Hemi V8) ,adding squish can help with tumble and swirl and give a more homogeneous mix of air and fuel , for a more complete burn .
 
This seems like a good moment to segue into a problem that I am having, if I may. My '76 Mk III has 750 type pipes from an unknown source, and had a pair of nice reverse cones silencers on them with the stock attaching brackets.

I like them just fine, but wanted to try a pair of Emgo reproduction Dunstall Decibles which I purchased, and have found that they don't match up with the brackets I have. I hadn't considered that happening...

The geometry and attaching points are now wrong. The reverse cones had the nice threaded bungs, whereas the Emgos have slotted rectangular blocks with a bolt that slides within it.

I saw a video of a Commando which had original Dunstalls and it appeared they had the same rectangular attaching brackets.

Is there a bracket which is known to work well for this combination? If not. I am prepared to fabricate.

Ed
 
Jdub said:
Hi to all, reviving this thread with a question: I am using standard 850 rose nuts with the Emgo non-balanced header set. Fully tightened, without any washer, there is rocking and room. With a single washer, slightly tighter, but with two I think I can tighten fully. So:

= I assume two washers, flat sides back to back, dome side one towards head, one towards pipe, for maximum seal?
= Has anyone introduced RTV hi-temp coating on these washers? Would that help the seal?
= Where may I purchase half-width rubber supports 06-0622 to tuck my exhaust pipe closer to the mounting / Z plate? I have searched RGM and elsewhere but no luck

Thank you for your replies!
Click to expand...
RTV high temp copper gets smeared around every ex. port retaining/seal surface every time the header pipe/s need refitting . Stuff's amazing .
 
As it turned out, all I had to do to use my stock brackets was be willing to flex the pipes a bit. I was trying to set everything up with no pre-load, just because I wanted to do the best job, but it occurred to me that these bikes were probably not built with "kid gloves", lol!

With everything loose, I put each silencer where it needed to be and tightened things up. Lastly, I finally got to use my new spanner and 2' bar on the rose nuts, fun!

I know I have read that some people leave the clamp between the silencer and pipe a little loose to allow for movement of the pipe. I did this considering that the front of the pipe moves with the engine and cradle, but the silencer mount brackets go to the frame.

It seems there would be an unavoidable exhaust leak as a result, but I can't see how else the engine / cradle can move freely?
 
I plan on just barely nipping the clamp so it won't move about and count on the lack of back pressure to prevent any leak. A hand over the end of a running bike's muffler would expose any leak I'd think?
 
Jdub said:
I plan on just barely nipping the clamp so it won't move about and count on the lack of back pressure to prevent any leak. A hand over the end of a running bike's muffler would expose any leak I'd think?
Click to expand...
Myself I get everything fitted with no tension moving the rear mounts so the rear rubbers are lined up as straight then tighten the roses while checking the rear and then tighten the clamp on the silencer to header. I like to use the barrel clamps from Paul Geoff on this connection.Other vendors sell these also.My rear rubber mounts have stayed good for some time with everything tight

Mike
 
Hi all, question on the stepped exhaust bracket 06.1721/S from AN. Using this bracket means routing the rear brake cable another way. I have tried moving it to the inside, between the inner exhaust bracket and the swingarm where a zip tie can keep it away from the swing arm. Does anyone have a more clever way to route this cable?

Pic below from rear, cable run blocked by stepped section and cannot run the cable above or below.

Exhaust with Two Crush Washers?
 
Jdub said:
Hi all, question on the stepped exhaust bracket 06.1721/S from AN. Using this bracket means routing the rear brake cable another way.
Click to expand...

That bracket is really intended for the right side only to increase kickstart clearance. Nevertheless the cable should still fit behind the inner plate as thats where the factory put it.

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Jdub said:
Hi all, question on the stepped exhaust bracket 06.1721/S from AN. Using this bracket means routing the rear brake cable another way. I have tried moving it to the inside, between the inner exhaust bracket and the swingarm where a zip tie can keep it away from the swing arm. Does anyone have a more clever way to route this cable?
Click to expand...

This is how I routed my rear brake cable so that the cable didn't chaff on anything

'74 Commando rear brakes feel unsafe.

When routing the brake cable between the inner muffler plate and the swingarm you need to make sure that there is an extra 3/8 inch diameter washer (.071 inch thick) on each Z-plate spacer. This will splay the Z-plate outward towards the rear which would give you more space between the swingarm...
www.accessnorton.com www.accessnorton.com

Peter Firkins
 
On the wings of angels - thank you for your replies. I thought the Service Bulletin of 1975 showed the rear brake cable "captured" within the L and R side exhaust/foot peg plate - seemed so clever to me. Now, I see that is not the case. L.A.B. post here discusses this subject and I should have spotted that before asking: https://www.accessnorton.com/Norton...te-rear-brake-cable-routing.27410/post-413593.

I will play with the stepped mounts being mindful of good header pipe seating to line the peashooters up from the back. All is vanity - thanks again!
 
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