Loose Exhaust Lockring (2017)

Mwood7800 said:

Drilled holes and wire for me. Both bikes trouble free. No brainer, 50 years

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Plenty of high heat copper silicone for me smeared around each piece ,snug down tight after alignments are good , go for a ride , retighten up. I eat the stuff for breakfast.

(my 2-cents) -- my 74 Mk2 came with the Mk3 style "flared" flange seating and collets. no crush washers used with this configuration. also used the andover-norton OE style lock rings. tool tightened the flange nuts and set the tabs on the lock rings. about 1500 miles now and no issues.

(FWIW) on the subject of safety wire, i'd just like to throw this out. do not substitute safety wire or lock wire for proper torque and assembly. there is a method and technique when using this stuff. I have seen more misuse of this of safety wire, especially In the (non-racing) automotive sector and lately, a few in the MC hobby. some light reading -- https://www.flight-mechanic.com/safetying-methods-part-one/

joe czech said:

tool tightened the flange nuts and set the tabs on the lock rings. about 1500 miles now and no issues.

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That's what they all say...until there IS an issue.
True, lock rings may stop unscrewing of the exh rose, but do not prevent the destroying of the threads as the pipe flange bangs around in situ. Keeps many repair facilities redoing port threads. I have done my fair share...
The lock rings belong on the "wall of shame" (IMO)

Notice the "join date" May 28, 2003, I was already in my second norton phase for 15 years when I signed up to this forum LOL

I used bronze exhaust rose and tighten / retighten over 3 heat cycles . A word of warning when tightening bronze roses with a C spanner - be certain that the fit of the spanner is such that the tooth on the spanner engages the fin at its root . If it doesn’t, regrind the spanner so that it does , otherwise you run the risk of breaking a fin . Don’t ask me how I know...

dynodave said:

That's what they all say...until there IS an issue.
True, lock rings may stop unscrewing of the exh rose, but do not prevent the destroying of the threads as the pipe flange bangs around in situ. Keeps many repair facilities redoing port threads. I have done my fair share...
The lock rings belong on the "wall of shame" (IMO)

Notice the "join date" May 28, 2003, I was already in my second norton phase for 15 years when I signed up to this forum LOL

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dyno - NOT (repeat NOT) trying to argue the point, but not following you here. if the rose nut is properly torqued (key word) and tabs set on the lock ring, how in the world will the rose nut back off enough (if any) to loosen, thus destroying the threads as the pipe flange bangs around. seems to me, once it locks the rose nut, it's not going anywhere UNLESS there's a mechanical failure of the fins on the cylinder head - or am I missing something? my (AN) lock rings have absolutely zero movement - tabs tight and secure to both the rose nut and cylinder head fins. i'm just wondering if folks are installing these things properly as designed (no flames to anyone).

I may be new to the Norton scene, but as a retired A&P mechanic and design engineer with 40+ years in aerospace, IMO, I can't see a real issue in the lock ring design - sorry, just not seeing it.

when I installed my lock rings, I had no information on how these things were installed and oriented to the rose nut and cylinder head. the lock rings have a natural curve which keeps them somewhat spring loaded in position. tab position to take advantage of cylinder head and rose nut fins. the cylinder head end tabs were factory formed and only the rose nut end required a set. couple pics of installation - issues???




sorry, can't see any way, anything's moving here....

The lock ring does loosen, the issue is that instead of the rose without a locking ring then backing out and becoming obvious it instead stops the rose from backing out but allows it to be just loose enough to vibrate and damage the alloy thread. You only catch it when the thread is unrecoverable. As soon as I read the NOC owners notes and read of the issue they were taken off my bike and went in the bin.

kommando said:

The lock ring does loosen, the issue is that instead of the rose without a locking ring then backing out and becoming obvious it instead stops the rose from backing out but allows it to be just loose enough to vibrate and damage the alloy thread. You only catch it when the thread is unrecoverable. As soon as I read the NOC owners notes and read of the issue they were taken off my bike and went in the bin.

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i'm sorry guys - still not following this - can't see how anything moves -- PUZZLED!

NOC notes published 1979

Worn exhaust, port threads: these are very often caused by allowing the nuts to come loose, but they are stopped from failing out by those rattley tab washers. The whole issue then vibrates and clatters, knocking out the threads.

kommando said:

NOC notes published 1979

Worn exhaust, port threads: these are very often caused by allowing the nuts to come loose, but they are stopped from failing out by those rattley tab washers. The whole issue then vibrates and clatters, knocking out the threads.

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one, "very often" - OK, not 100% of the time. two, "caused by the nuts to come loose" - again, I understand that. three, clarify - "are stopped from failing out..." failing out - ??? fourth, rattley tab washers - this is what I don't understand - if they are loose and rattle, I take that as not properly installed and could allow movement of the rose nut, BUT, I would think movement would be somewhat limited due to the pure nature of the tab design. mine are firm and secure - no movement, no rattle. I know it's NOC and goes back 40 years and i don't mean to ruffle any feathers or anything - JUST NOT UNDERSTANDING THIS.

one thing I've learned from some of my other interests and ventures, at some point you realize you may be in over your head and you need to back away. I think I may have reached that point -

The logic, as I see it, is that the retaining rings try to hold the nut still. Whereas (as you showed in your link) lock-wiring keeps nuts under tension in the direction of tightness.

So, if the sealing ring etc compresses just slightly, the nut will become loose in the thread. Then, because the lock ring still looks correct, even a reasonably attentive owner may think all is well, until the threads had become quite badly damaged through vibration induced chatter.

joe czech said:

if the rose nut is properly torqued (key word) and tabs set on the lock ring, how in the world will the rose nut back off enough (if any) to loosen, thus destroying the threads as the pipe flange bangs around. seems to me, once it locks the rose nut, it's not going anywhere UNLESS there's a mechanical failure of the fins on the cylinder head - or am I missing something?

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The rose nut loosens as the crush washer settles. I have had to tighten my exhaust on the road many times even after putting the fear-of-God into the spanner. Any time you remove the exhust and install new crush washers you WILL have to retighten them a few times after heat cycles. If you're stupid enough to use those tabs you won't know when they're loose. I bought my 850 new, used the tab locks, and had to have the head sleeved because of them. No joke.

maylar said:

The rose nut loosens as the crush washer settles. I have had to tighten my exhaust on the road many times even after putting the fear-of-God into the spanner. Any time you remove the exhust and install new crush washers you WILL have to retighten them a few times after heat cycles. If you're stupid enough to use those tabs you won't know when they're loose. I bought my 850 new, used the tab locks, and had to have the head sleeved because of them. No joke.

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"If you're stupid enough..." ouch - . I get the crush washer settling thing and the heat cycles. after my initial tightening (and a few taps with a dead blow hammer), 2X heat cycles, a few miles, and re-tight, before setting the tabs. months now and everything seems secure. obviously you guys know more about this than I do. I must be missing something and not seeing the big picture. moving on....

Whether the crush washer deforms from vibration , or the aluminum head thermally grows away from the steel nut threads and creates a physical clearance or loosness though no "rotation has occurred are the variables that are not necessarily verified in each or any case. It does seem, in real world practice, the retaining compression needed goes away. How many thousands of norton heavy twins have bad or damaged ports and this would seemingly have been aggravated by the iso mounted commando. Even flat spherical/cone mount MKIII and aftermarket style (no crush washer) still have suffered this fate.
Makes you wonder of the physics involved in this area of the bike considering all the broken balance pipe 850's.

Brooking 850 said:

Here is the method I use for both my road and race bike.
Also use it for the 2EX1 systems I am fabricating.
Use the AN lock ring with tabs, cut off the tabs ( I then HPC coat what now becomes big washers) drill and tap the 3 x flats on the exhaust roses, use grub screws to tighten against the big washer ring once the exhaust roses are tight.
Repeat sequence after a couple of heat cycles.
Never come loose.
Regards Mike
View attachment 69288Regards Mike

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Very smart modification ...do you still fabricat these exhaust systems ?
I'm also from Tga

Anyone who puts the threaded gizzmo's In without Lube or anti sieze paste , is asking for trouble .
NEW gaskets compress , so you lean on the spanner for the first week , post ride , while its hot .,
Then after theyve settled and've stopped shifting , you can tweek the tabs on the lock tabs .

Though your unlikely to need them . Drilled & saftey wired'd be more ' Hi tech ' & period apt .