1973 850 Rebuild

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Might as well enquire what is the preferred engine oil.
Some like composite, some like copper.
I've had good luck with copper. Anneal with a propane torch until it turns red. Let it cool and clean up with scotch-brite. A very light coat of K&W CopperCoat spray when you are ready to install.
I've never used the composite on a Commando, but lots of people do.
Do you need to anneal on a brand new copper gasket or only when reusing?
 

robs ss

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Do you need to anneal on a brand new copper gasket or only when reusing?
Always do it - copper work hardens.
One thing I didn't know until quite recently is that, with copper, it doesn't matter if you quench it from red hot or let it cool in air - the annealing effect is the same (unlike steel!)
 

texasSlick

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Always do it - copper work hardens.
One thing I didn't know until quite recently is that, with copper, it doesn't matter if you quench it from red hot or let it cool in air - the annealing effect is the same (unlike steel!)

At the risk of starting an argument, I will state that robs ss is absolutely correct in his statement regarding quench or air cool, but IMO, annealing a new copper gasket is unnecessary, and is likely to result in more re-torque to finally settle in a new gasket.

Why? Copper "creeps" under compressive load. This means it flows away from the pressure on it, and lessens the torque producing the compressive load. As rob states, copper work hardens, thus a retorque hardens the metal, and reduces the "creep" effect. So, in essence, if you anneal copper to full soft, you will likely need at least one retorque to get back to where it becomes work hardened to resist creep.

Go to websites of copper gasket manufacturers ..... most will state their gaskets are OPTIMALLY annealed. They do not state to what hardness, as that is proprietary information. You destroy that optimal annealing by flame annealing to full softness.

There, I've said it, now I will don my flak jacket .....

Slick

PS .... no copper gasket manufacturer includes instructions with their product to "anneal before using"
 

gortnipper

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At the risk of starting an argument, I will state that robs ss is absolutely correct in his statement regarding quench or air cool, but IMO, annealing a new copper gasket is unnecessary, and is likely to result in more re-torque to finally settle in a new gasket.

Why? Copper "creeps" under compressive load. This means it flows away from the pressure on it, and lessens the torque producing the compressive load. As rob states, copper work hardens, thus a retorque hardens the metal, and reduces the "creep" effect. So, in essence, if you anneal copper to full soft, you will likely need at least one retorque to get back to where it becomes work hardened to resist creep.

Go to websites of copper gasket manufacturers ..... most will state their gaskets are OPTIMALLY annealed. They do not state to what hardness, as that is proprietary information. You destroy that optimal annealing by flame annealing to full softness.

There, I've said it, now I will don my flak jacket .....

Slick

PS .... no copper gasket manufacturer includes instructions with their product to "anneal before using"
 

grandpaul

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I've installed at least 80 new copper head gaskets, NEVER annealed one, NEVER had a failure. (Norton, Triumph & BSA big twins combined)

I've installed 20+ composite ones and only had ONE failure. I may not have done a proper re-torque, I had four simultaneous projects going and got ahead of myself, so I don't blame the high quality gasket I got from Old Britts (the replacement didn't fail)

...just "For What it's Worth"...
 
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Mofosheee

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Adjustable Ikon shocks are hard to beat for the money along with adjustable compression/rebound inserts for the forks.

As far as the swingarm spindle and bushes, it seems a lot of people simply jam the thing together (Maybe even sand paper the bush ID) then in some cases force the swingarm over the cradle then wonder why the thrust faces of the bushes show wear or galling.

With modification you can add PTFE thrust washers along with a few other things. (Including machining a facing mandrel that uses the cradle spindle bore with the stock thrust set up)
I'm interested in the PTFE mod that you mentioned. Makes sense and appears simple to do while the bike is apart. I'm holding off on installing the swing arm hoping someone might have information on this. My search of this forum and net yielded nothing.
 
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HRD

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MichaelB

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Interesting bush HRD.
Do you have any experience with it?
 

Mofosheee

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There is another type of swingarm bush made from Ertalyte Tx that is for sale at https://www.ebay.com.au/itm/Norton-...868900?hash=item289c978a64:g:Ks4AAOSwyf1bQoHd
I have no connection to the seller.
Thank you for responding. I had visions of a simple PTFE washer that went between the face of the bronze bushing that rides against the transmission/swingarm cradle. This is much more than I expected. Probably over kill for me.
There is another type of swingarm bush made from Ertalyte Tx that is for sale at https://www.ebay.com.au/itm/Norton-...868900?hash=item289c978a64:g:Ks4AAOSwyf1bQoHd
I have no connection to the seller.
 

robs ss

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At the risk of starting an argument, I will state that robs ss is absolutely correct in his statement regarding quench or air cool, but IMO, annealing a new copper gasket is unnecessary, and is likely to result in more re-torque to finally settle in a new gasket.

Why? Copper "creeps" under compressive load. This means it flows away from the pressure on it, and lessens the torque producing the compressive load. As rob states, copper work hardens, thus a retorque hardens the metal, and reduces the "creep" effect. So, in essence, if you anneal copper to full soft, you will likely need at least one retorque to get back to where it becomes work hardened to resist creep.

Go to websites of copper gasket manufacturers ..... most will state their gaskets are OPTIMALLY annealed. They do not state to what hardness, as that is proprietary information. You destroy that optimal annealing by flame annealing to full softness.

There, I've said it, now I will don my flak jacket .....

Slick

PS .... no copper gasket manufacturer includes instructions with their product to "anneal before using"
You're absolutely right Slick - but what you don't mention there is the reason behind the desirability of that creep. (just for those that might not know):
In its soft state the copper will, on first torquing, deform to accommodate the imperfections in the mating surfaces.
Once that is out of the way, you want a stiffer gasket to prevent relaxing the torque (tension).
I routinely anneal to ensure I have the gasket in its "soft" form.
Quite a few years ago I had a gasket leak from new - had the gasket been deformed and restraightened thus hardening some of it?
I'll never know - but I always anneal - to be sure, to be sure!
 

texasSlick

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@robs ss reply #151

Rob .... you are absolutely right regarding the fact that soft copper will deform better to rectify imperfections in the sealing surface. T Warp also alludes to this fact.

However, I do not apply a gasket to any surface that is imperfect.
I prefer to spend my time making a surface proper, than annealing a gasket to accommodate an improper surface. Would you not agree the first approach is a better guarantee of success?

For those who feel annealing yields an additional modicum of success, I say "Fine! Just be sure to re-torque as many times as necessary until the gasket becomes stable."

Regarding how many re-torques are necessary, and the intervals between, there is no magic "fits all" formula. Keep checking until the gasket becomes stable.

Slick
 
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Time Warp

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I'm interested in the PTFE mod that you mentioned. Makes sense and appears simple to do while the bike is apart. I'm holding off on installing the swing arm hoping someone might have information on this. My search of this forum and net yielded nothing.

Its just that but until proven long term would not recommend it. (The bronze bush flanges need irreversible machining on the thrust faces)
 

Mofosheee

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Its just that but until proven long term would not recommend it. (The bronze bush flanges need irreversible machining on the thrust faces)
Agree, I'm finding zero history on the ebay product listed above (post #150). With that I'll stay away.
 

robs ss

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@robs ss reply #151

Rob .... you are absolutely right regarding the fact that soft copper will deform better to rectify imperfections in the sealing surface. T Warp also alludes to this fact.

However, I do not apply a gasket to any surface that is imperfect.
I prefer to spend my time making a surface proper, than annealing a gasket to accommodate an improper surface. Would you not agree the first approach is a better guarantee of success?

For those who feel annealing yields an additional modicum of success, I say "Fine! Just be sure to re-torque as many times as necessary until the gasket becomes stable."

Regarding how many re-torques are necessary, and the intervals between, there is no magic "fits all" formula. Keep checking until the gasket becomes stable.

Slick
Yes - I do agree in ensuring the faces to be joined should be made as good as possible - although reaching perfection might be hard.
What I meant was the soft copper will accommodate the remaining imperfections.
If the surfaces were absolutely perfect ad alloy head would stick to and alloy barrel much like 2 gauge blocks left together too long - they'll actually weld themselves together - no need for any gasket then.
 

HRD

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Interesting bush HRD.
Do you have any experience with it?
Not as yet and intend to purchase and use.The seller has been making and selling for a couple of years and is on the "Made in England" forum uses name Combat Pete ,been around for some time,he may be on this Forum ?
 

MichaelB

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It does look interesting..
Anyon else here have experience with these?
 

Time Warp

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Thanks for the clarification.................PTFE isolastic parts
Not to take away from those fancy 'plastic swing arm bushes.

If the cradle thrust faces were not in premium surface condition ?
If the eyes on the swing arm were not inline ?

Then what, you would have the same issues as per bronze bushes. If the spindle is a nice fit (in bronze) , gets some lubrication and the swing arm does not have to be levered onto the cradle being to tight they work as good as anything (maybe for 50 years)
 
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