Re: MK3 Exhaust Ring Question

I think that a Mk3 uses short thread rings to allow for the spherical seating/sealing washer and also the exhaust balance pipe. What sealing washers have you used?

Also, are the pipes the type designed for the spherical seal, or the flat seal?

Hi Steven

If you fitted a crushable gasket it would account for the excess thread. Take a look at the attached link, as Allen indicated there is no requirement for a crushable gasket.

https://andover-norton.co.uk/en/shop-drawing/147/exhausts-mufflers-passenger-footpegs

Regards

Katherine

Dear Steven,

Having looked at your pictures, part of your visual problem is that something is missing from each side. You need the exhaust nuts to have a gap, threaded or not, to accomodate the lock washers. If you run without these it won't be long before exhausts come undone and then damage thread.

NB If you have not fitted these before, they omly fit one way round as tabs have different spacings for gap in fins/ exhaust nut.

regards Martin

Steven,

That amount of thread showing on the right looks just like my 1975 Mk3, but the left is a bit long. I wouldn't worry as long as you have got the right pipes and washers* but look at the Andover Norton site drawings.

You do not need lock tabs, just copper grease the threads and do them up with the proper C-spanner plus a two foot extension bar. Threads that size will take 200 ft/lbs or more and at least 100 ft/lbs is needed to stop them vibrating loose. It is when they come loose that the threads are damaged.

Remember to tighten all the parts in the right sequence: first get the silencers all aligned while the exhaust nuts are slack, then the exhaust nuts, and finally the balance pipe bolts.

Norm

* EDIT: I used the word washer and I shouldn't. There is a metal spherical seating between the spherical ended pipe and the head (check there are not two in there now!) and the nut grips the pipe flange by means of a split collet. https://andover-norton.co.uk/en/shop-drawing/147/exhausts-mufflers-passenger-footpegs

I can't agree that the exhaust lockings are necessary, or even useful. I never use them.

Instead, do up the exhaust nuts as follows (assuming that you are facing a cold engine:

1. Tighten, but don't go mad
2. Take the bike for a ride until the engine is at working temperature
3. Tighten very firmly (I use an 18" Stillson on the fins)

In my experience all the various types of C-spanner sold for this job are useless, hence the Stillson (in use since 1974).

Previously Martin Freeman wrote:

Dear Steven,

Having looked at your pictures, part of your visual problem is that something is missing from each side. You need the exhaust nuts to have a gap, threaded or not, to accomodate the lock washers. If you run without these it won't be long before exhausts come undone and then damage thread.

NB If you have not fitted these before, they omly fit one way round as tabs have different spacings for gap in fins/ exhaust nut.

regards Martin