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Exhaust clamp unscrewing

Submitted by simon_amos on Mon, 11/08/2014
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Hi All,

I took my model 19 outfit on a 400 mile trip fully loaded with passenger and luggage recently and though the bike generally ran well, I developed a problem with the stainless exhaust clamp I bought from armours unscrewing itself. The first time it happened I noticed some of the threads had also stripeed from it. I managed to tighten it up with a wrench, but it gradually became a bigger and bigger problem and I was eventually left to ride the final 40 miles or so home with no thread left to grip.

Two questions - before I start taking off the head, is it likely to have stripped the head threads or just the clamp? Also, would a different type of clamp lock better, or should I be considering an additional plan to keep it in place?

There's nothing worse than having a lovely old slogger that you can't open up to slog up the hills..!

Mark

Submitted by dave_graham1 on Mon, 11/08/2014

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They're usually wire locked with a small hole drilled in one of the clamp fins and one on a cylinder head fin. There is a large tab washer that fits the Dommie and Commando clamps, I don't know if there is one for the singles.

Submitted by neil_wyatt on Tue, 12/08/2014

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Yes Dave, mine came away on my way to taking my 1955 19S for MOT preparation in 1974. Ray Chase in Ripon tightened it up and wired it up as described above and never caused any further trouble.

A little later, people were telling me about flames coming from under the petrol tank! I just thought it sounded a bit loud....

My 19S had a single seat Watsonian sidecar attached.

Submitted by svein_marken on Tue, 12/08/2014

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Hi,I have drilled asmall hole at a fin on thecylinder head andat a clamp fin and use a spring and not wire.I have used this about 30 years on my 1955 19S and it works very well.Good luck!

Regards from Svein.

Submitted by simon_amos on Wed, 13/08/2014

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Thanks to all for your suggestions - sounds like everybody agrees drilling and wiring is the way forward...

Mark

Previously svein_marken wrote:

Hi,I have drilled asmall hole at a fin on thecylinder head andat a clamp fin and use a spring and not wire.I have used this about 30 years on my 1955 19S and it works very well.Good luck!

Regards from Svein.

Submitted by albert_sheean on Sun, 17/08/2014

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I had this problem too, not only did the exhaust rose nut get loose, the copper asbestos washer would disintegrate as well. Living in the USA made it a bit hard to pop over to my local Norton spares stockist. I resorted to making a copper washer out of 1/8" soft copper tubing bent into a circle and the ends butted together closely. Next I drilled a hole in one of the rose nut fins and fitted a spring that hooks over one of the valve cover hold down bolts. I always smear a bit of anti-sieze compound on the rose nut threads as well.

 


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