Exhaust nut question

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joe czech said:
OK guys, you win. i guess i'm not seeing the big picture, and being rather new to this stuff, all i can do now is keep an eye on things. i do that anyway with periodic imspections. not going to change things now, in fact wouldn't have any idea what would be a better way. peace....
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That's what I would do Joe. Check often and be sensitive to it.
Maybe you'll never have an issue.
But, As soon as 1 got loose, they both come off, retorque with fresh washers and copper anti seize.
With the rings off, check often with a wrench, 'hot', and keep them tight.
I do it after an all day ride. I grab the wrench and give a tug while it's hot.
Sometimes it nips, sometimes it doesn't. But now I rest easy.
It's just one of those 'Norton' things.

BTW, a quality, proper fitting wrench is important....
 
MichaelB said:
That's what I would do Joe. Check often and be sensitive to it.
Maybe you'll never have an issue.
But, As soon as 1 got loose, they both come off, retorque with fresh washers and copper anti seize.
With the rings off, check often with a wrench, 'hot', and keep them tight.
I do it after an all day ride. I grab the wrench and give a tug while it's hot.
Sometimes it nips, sometimes it doesn't. But now I rest easy.
It's just one of those 'Norton' things.

BTW, a quality, proper fitting wrench is important....
Click to expand...
one thing i've found out on this thread is, this is one tough crowd. ;)

i have to mention, my exhaust system has the flared header pipes, same as the Mk3 commandos. it does not have the crush washers like earlier models. with the flared header, it also utilizes a two piece retaining collet and a coned spherical seating washer to seal the pipe to the head. my 74 is a late build, and it seems like some of the Mk3 features may have worked into my Mk2.

one question (i'm thinking LAB can answer this one) - do Mk3 bikes utilize the locking ring tab washers, or did that feature end with the 74 model year? if the Mk3's didn't use the locking ring tab washer, what did they use? i can't find anything addressing this on the AN site.
 
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joe czech said:
one thing i've found out on this thread is, this is one tough crowd. ;)

i have to mention, my exhaust system has the flared header pipes, same as the Mk3 commandos. it does not have the crush washers like earlier models. with the flared header, it also utilizes a two piece retaining collet and a coned spherical seating washer to seal the pipe to the head. my 74 is a late build, and it seems like some of the Mk3 features may have worked into my Mk2.

one question (i'm thinking LAB can answer this one) - do Mk3 bikes utilize the locking ring tab washers, or did that feature end with the 74 model year? if the Mk3's didn't use the locking ring tab washer, what did they use? i can't find anything addressing this on the AN site.
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Smear up everything (clean internal contact points ) , with high - temp copper silicone . Be generous.
Tighten up with all your strength. Using the special wrench of course.
Start up and get her hot.
Re-tighten with the special tool , smacking it all tight with a 5 Lb. sledgehammer.
Go for a drive and do it ( sledge to tool smacking ) again.
Drive.
5 th Norton , never needed re-threadings or any backing offs doing this. Enjoy.
 
Torontonian said:
Smear up everything (clean internal contact points ) , with high - temp copper silicone . Be generous.
Tighten up with all your strength. Using the special wrench of course.
Start up and get her hot.
Re-tighten with the special tool , smacking it all tight with a 5 Lb. sledgehammer.
Go for a drive and do it ( sledge to tool smacking ) again.
Drive.
5 th Norton , never needed re-threadings or any backing offs doing this. Enjoy.
Click to expand...
Exactly what I do. Except perhaps not the 5 lb sledge. I just lean on it with the proper tool several times when hot.

The secret is the high temp rtv.

The tabs let it rattle a mm or two back and forth and ruin the threads.. The spring and lock wire looks fine on a race bike but a bit rough on s street bike I think.

Worked for me for 20 years at least.
 
The issues, as a see it, with the infamous tabs is NOT that they allow the nuts to ‘come loose’ by actually unscrewing (or should not).

The issue is that the washers and the joint in general compress. This is clear to see when fitting pipes with new washers etc as they take several re torques, over a few miles, until things settle down. Therefore, if this is not done, the clamping force will be removed from the nuts rendering them ‘loose’.

Then, as others have said, the tabs do a a great job of holding the nuts in this slightly loose state, not loose enough to be visually obvious, but loose enough to fret and thus chew up those soft alloy threads.
 
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joe czech said:
one question (i'm thinking LAB can answer this one) - do Mk3 bikes utilize the locking ring tab washers, or did that feature end with the 74 model year? if the Mk3's didn't use the locking ring tab washer, what did they use? i can't find anything addressing this on the AN site.
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AN list the rings for 74, not on the 75 drawing they use and nothing is there to replace it. That does not mean they weren't used as AN can make errors, only a MK3 owner would know.
 
Fast Eddie said:
The issues, as a see it, with the infamous tabs is NOT that they allow the nuts to ‘come loose’ by actually unscrewing (or should not).

The issue is that the washers and the joint in general compress. This is clear to see when fitting pipes with new washers etc as they take several re torques, over a few miles, until things settle down. Therefore, if this is not done, the clamping force will be removed from the nuts rendering them ‘loose’.

Then, as others have said, the tabs do a a great job of holding the nuts in this slightly loose state, not loose enough to be visually obvious, but loose enough to fret and thus chew up those soft alloy threads.
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that what i was getting at - my bike does not utilize the crush washers. again, my 74 Mk2 (late build, and best i can tell) originally came from the factory with Mk3 exhaust, conical-spherical washers and flared header pipes. basically, it depends on flared surfaces for sealing. wondering if the crush washer design contributes to the exhaust nut loosening over time? QUESTION MAYLAR - you'r bike was built with a coffee break of mine - do you have your original header pipes? if not, do you know what was original to your bike - Mk2 style or Mk3?
 
kommando said:
AN list the rings for 74, not on the 75 drawing they use and nothing is there to replace it. That does not mean they weren't used as AN can make errors, only a MK3 owner would know.
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are the AN part illustrations based on factory documentation?
 
joe czech said:
QUESTION MAYLAR - your bike was built with a coffee break of mine - do you have your original header pipes? if not, do you know what was original to your bike - Mk2 style or Mk3?
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Original pipes on my MKII were crossover 850 type with the split collars and short rose nuts. Also had the lock tabs.
 
joe czech said:
that what i was getting at - my bike does not utilize the crush washers. again, my 74 Mk2 (late build, and best i can tell) originally came from the factory with Mk3 exhaust, conical-spherical washers and flared header pipes. basically, it depends on flared surfaces for sealing. wondering if the crush washer design contributes to the exhaust nut loosening over time? QUESTION MAYLAR - you'r bike was built with a coffee break of mine - do you have your original header pipes? if not, do you know what was original to your bike - Mk2 style or Mk3?
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I’ve no experience with the MK3 set up but my guess would be there is still some ‘give / crush / settling’ in the joint, although I imagine much less than the crush washers.
 
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johnm said:
Exactly what I do. Except perhaps not the 5 lb sledge. I just lean on it with the proper tool several times when hot.

The secret is the high temp rtv.

The tabs let it rattle a mm or two back and forth and ruin the threads.. The spring and lock wire looks fine on a race bike but a bit rough on s street bike I think.

Worked for me for 20 years at least.
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NO FLAMES or anything, but RTV is meant to be a sealant, not a thread locker. i personally wouldn't depend on it's locking ability. just my 2-cents.

one thing to note on the lockring tabs - there are four surfaces of each side of the tabs that lock into the fins of either the head or the exhaust nut. the spacing on these tabs, in relation to the fins, is such that at least one surface of the tab is an interference or friction fit with the corresponding surface of the fin. at least in my case, there is no movement, CW, CCW, or whatever. again i can't see there is any rattle movement, looseness, or anything in my tab lockrings.
 
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Fast Eddie said:
I’ve no experience with the MK3 set up but my guess would be there is still some ‘give / crush / settling in the joint, although I imagine much less than the crush washers.
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I use the MK3 setup on my MK2 and there is less give as no sealing washers, the conical/spherical seat gives a good seal but is also solid.
 
Fast Eddie said:
I’ve no experience with the MK3 set up but my guess would be there is still some ‘give / crush / settling in the joint, although I imagine much less than the crush washers.
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yes, the initial torque on the exhaust nut would form or match, or settle in, the flared end of the header pipe to match the conical washer. the other side of the washer is flat and mates to the formed flat within the cylinder head. the washer does not have any "crush" characteristics like the Mk2 version sealing washers. once the flare surfaces mate and seal, and as long as they're undisturbed, things shouldn't change. in theory, should work much like your brake lines/hoses. if that IS the case, and maybe i'm just lucky, but i'm just not seeing a problem. again, not trying to be arguementative.
 
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joe czech said:
that what i was getting at - my bike does not utilize the crush washers. again, my 74 Mk2 (late build, and best i can tell) originally came from the factory with Mk3 exhaust, conical-spherical washers and flared header pipes. basically, it depends on flared surfaces for sealing. wondering if the crush washer design contributes to the exhaust nut loosening over time?
Click to expand...

The 062412 tab washers are not listed in the Mk3 parts book, possibly because the flared pipes don't have crush washers so the tabbed washers were deemed unnecessary?
According to the Mk2/2A supplement, the 'Mk3' flared header pipes (065256 & 065257) were introduced on the Mk2A although it's possible they were also fitted to some late Mk2 models.
 
OK - my final word on the subject. you folks are a tough crowd - i don't think i can win any argument here. with that, i'll keep doing what works for me and it's obvious you people are doing what works for you. if i need to change things down the road, i will adjust accordingly. peace....
 
joe czech said:
NO FLAMES or anything, but RTV is meant to be a sealant, not a thread locker. i personally wouldn't depend on it's locking ability. just my 2-cents.

one thing to note on the lockring tabs - there are four surfaces of each side of the tabs that lock into the fins of either the head or the exhaust nut. the spacing on these tabs, in relation to the fins, is such that at least one surface of the tab is an interference or friction fit with the corresponding surface of the fin. at least in my case, there is no movement, CW, CCW, or whatever. again i can't see there is any rattle movement, looseness, or anything in my tab lockrings.
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Fair enough. The soft lock seal of the high temp RTV is exactly what works in my opinion but use what works for you.

Works on my 74 850 commando and 500 cc race bike for many seasons.
 
L.A.B. said:
According to the Mk2/2A supplement, the 'Mk3' flared header pipes (065256 & 065257) were introduced on the Mk2A although it's possible they were also fitted to some late Mk2 models.
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Joe's bike was built the same day as mine, and I would bet it was assembled with the same 850 MKI style head pipes.
 
maylar said:
Joe's bike was built the same day as mine, and I would bet it was assembled with the same 850 MKI style head pipes.
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can't say and can't proved one way or another. if someone previously replaced the header pipes, why would they go with the Mk3 design, especially since there's collets, conical washers, and exhaust nuts that would also have to be replaced. why wouldn't they just order up the same replacement Mk2 parts? now whether my bike came with lockring tab washer, i don't know. when i bought my bike, the locknuts were half-assed lockwired. i did find a used set of lockring washers in some parts boxes, and when i went through the recondition effort, i bought new and installed accordingly. can't say one way or another, but i wouldn't bet against my exhaust not being OE original.

BTW, when i say half-assed lockwired, i mean there was a loop of safetywire looped from one exhaust nut to the other - wasn't twisted, or one nut pulling against the other - just a loop of wire. wasn't doing a friggin thing! pretty obvious that someone didn't have a clue on the mechanics of safety wire.
 
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joe czech said:
can't say and can't proved one way or another. if someone previously replaced the header pipes, why would they go with the Mk3 design, especially since there's collets, conical washers, and exhaust nuts that would also have to be replaced. why wouldn't they just order up the same replacement Mk2 parts?
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The original setup was no bargain. Alignment with the crossover pipe was critical and the head pipes tended to crack at the welds. Perhaps someone figured that the MKIII design was superior and opted to take their chances with it.
 
joe czech said:
if somewhere previously replaced the header pipes, why would they go with the Mk3 design, especially since there's collets, conical washers, and exhaust nuts that would also have to be replaced.
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The exhaust nuts (063988) are the same (all 850).
The 065260 Mk3 collets are 'one piece' (x2) and what AN sells instead of the previous 063990 x4.
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