exhaust nuts
- Thread starter htown16
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All norton twin exhaust ports are almost exactically 3/4" deep.
The parts book does not show different exhaust nuts for 650 at least for 63 up. I see no need for a different nut going all the way back to my 1949 M7 engine and all the other engines I own, both 20 degree or 40 degree ports... up to my 73-750....The nuts and thread length are dependent on the type of pipe end you are trying to hold in. 06-3988 73-75 850 should be the shortest thread due to the pipes. 850 have bigger squarer fins. Early are smaller and have a more rounded fin.
The parts book does not show different exhaust nuts for 650 at least for 63 up. I see no need for a different nut going all the way back to my 1949 M7 engine and all the other engines I own, both 20 degree or 40 degree ports... up to my 73-750....The nuts and thread length are dependent on the type of pipe end you are trying to hold in. 06-3988 73-75 850 should be the shortest thread due to the pipes. 850 have bigger squarer fins. Early are smaller and have a more rounded fin.
concours
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Some pictures (and light reading) for you here: engineering-compromises-leading-exhaust-threads-stripped-t14363.htmlhtown16 said:
htown16
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Here's the pics
The one on the far right is definitely off of a 750, middle right I believe is an 850 and the two on the left are the ones in question.
I really can't see much difference in any of them.
The bike in question is a 1974 850 with a rh4 head.
I definitely want to fit the 750 pipes without the crossover a) I think they look better b) the cross over pipe was a major pia on my Bonneville c) I already have a pair
I antisieze everything that is a two metal contact and I learned to leave the outer tab washers off on my 72 rebuild.
If you think the Norton design is a compromise check out a 750 Triumph where you push the pipes into the head and hope for the best.
Concour's
Where did you get the nut on right in your picture?
Htown
The one on the far right is definitely off of a 750, middle right I believe is an 850 and the two on the left are the ones in question.
I really can't see much difference in any of them.
The bike in question is a 1974 850 with a rh4 head.
I definitely want to fit the 750 pipes without the crossover a) I think they look better b) the cross over pipe was a major pia on my Bonneville c) I already have a pair
I antisieze everything that is a two metal contact and I learned to leave the outer tab washers off on my 72 rebuild.
If you think the Norton design is a compromise check out a 750 Triumph where you push the pipes into the head and hope for the best.
Concour's
Where did you get the nut on right in your picture?
Htown
Those all look like 850's to me, but regardless, I believe if you search the venders you can find the non balanced pipes as per the 750 but with the bell mouths like the 850. This will allow you to use the convex washer and split collet arrangement as you probably have now. I like this because it allows a gimbal like adjustability rather than just the back and forth adjustability of the flat flange and gasket arraignment. This makes it easier, in my opinion, to line up the whole exhaust system without straining anything.
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up to 72 are 06-2464 750 of course and .73" small fin
73 750 are 06-3555.... probably big fin but are .72"
I only have one of these. I think these are the ones BCS has/had on sale a while back.
73-75 850 are 06-3988 and are about .60 -.62" deep and big fin
Probably a new big fin design for 73 with different finish dimension for the different pipes...therefore a different PN.
73 750 are 06-3555.... probably big fin but are .72"
I only have one of these. I think these are the ones BCS has/had on sale a while back.
73-75 850 are 06-3988 and are about .60 -.62" deep and big fin
Probably a new big fin design for 73 with different finish dimension for the different pipes...therefore a different PN.
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What matters is the rose nut threaded section is long enough to seat on header flange and trap it fixed against the exhaust port sealing flat. Anything that can crush down over time is taboo to use as can beat down loosing clamp force even though rose nuts don't move and wired or lock washer in place the slack developed beats the head threads to dust. Just make sure the rose nuts don't seat on outer head rather than inner flanges. Milk of Magnesia works a treat as anti-seize here having experienced a few times now on its self locking effect till nut is 1st moved some then acts as slight lube to ease backing off. MoM put on wet helps lube the severe torque required to avoid head damage and WILD NOISEs suddenly on the fly.
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I prefer to use solid sealing washers either aluminium or copper. I am lucky a previous owner had the head welded up between fins on both ports and fitted 2 studs on each exhaust. Its not original but those buggers never have worked loose. The 750 is still original and so far has not worked loose, but its my restoration baby so it doesn't get much use.
SteveA
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Beach said:
Or use thicker manifold gaskets like these....
http://www.ebay.co.uk/itm/390706093945? ... 1423.l2649
I have some of these but I have a custom race exhaust with a 5mm flange fitting so I would like to find some thinner seals, but maybe not the stock steel ones hence the question about where to get solid copper seals.....
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htown16 said:Here's the pics
The one on the far right is definitely off of a 750, middle right I believe is an 850 and the two on the left are the ones in question.
I really can't see much difference in any of them.
The bike in question is a 1974 850 with a rh4 head.
I definitely want to fit the 750 pipes without the crossover a) I think they look better b) the cross over pipe was a major pia on my Bonneville c) I already have a pair
I antisieze everything that is a two metal contact and I learned to leave the outer tab washers off on my 72 rebuild.
If you think the Norton design is a compromise check out a 750 Triumph where you push the pipes into the head and hope for the best.
Concour's
Where did you get the nut on right in your picture?
Htown
I will add more difficulties on this thread - and I NEED MORE HELP
I have one 1974 Norton commando 850 on restoration - BUT with a R10 head (as PO stated) and balanced pipes
The Exhausts rose nuts are in very BAD condition and change is needed -
https://picasaweb.google.com/lh/photo/A ... directlink
https://picasaweb.google.com/lh/photo/x ... directlink
What kind of exhaust rose nut I must BUY ???
I had a hard time getting crush washers to work with a 1970 Fastback and pipe was coming loose. I ran out of washers and was even trying to stack them in the exhaust while on a road trip. Used an old fork bushing and cut it to fit and have never had to go back to tighten. I always safety wire also. I believe that safety wire that constantly pulls a nut towards the engine saves cylinder head threads.
Mike
Mike
Just an fyi related comment.
I used to use the Suzuki GS model type crush washers with the 850 nuts on my 750 (available at any dealer). They gave ample space for the mismatch.
When I got the bronze nuts from Walridge they did not hold well with these very crushable washers. For me, the OEM washers work the best with the bronze nuts.
I used to use the Suzuki GS model type crush washers with the 850 nuts on my 750 (available at any dealer). They gave ample space for the mismatch.
When I got the bronze nuts from Walridge they did not hold well with these very crushable washers. For me, the OEM washers work the best with the bronze nuts.
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