250 exhaust diameter

[kaysystems]

Hi

Can someone please tell me some details of the Mach 1/Mark3 original chrome muffler? I'd like to know what the diameter of the exit should be. I read that the inlet of the mullers were all the same diameter, but Mach 1/Mark 3 ones had a different exit diameter than the Monza etc.
I have a muffler in storage and would like to find out if it is correct for my 66 Mark 3

Thanks in advance

David

[nalimugmug]

Mach 1 Exhaust Pics

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[Bevel bob]

That exhaust appears too new for an orriginal . For many years replacements have been one size fits all ,(understandably!) , but that does not mean its correct . The Mach 1 and Mark 3 NC have a cam that needs to work with a free flowing exhaust.I have memory of a new Mach 1 with a bigger outlet than that shown.

[nalimugmug]

Hi Bob,

The reason the exhaust looks new is that i have had it fully restored, this to include the logo being reingraved and the whole silencer rechromed.

Checking on my other Mach 1s, the outlet diameter of the restored item is exactly the same, however, the exhaust on AVG is not correct

Pics of before and after engraving of logo.

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Regards

Bob

[nalimugmug]

Hi again,

As Bevel Bob correctly states the exhaust of the Mach 1 and Mark 3 were designed to be as non restrictive as possible.

Many moons ago I took apart a 'lesser' silencer and a Mach 1 to compare the differences.

The differences can be clearly seen from the pics, however the baffles do appear to be the same.

Regards

Bob

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[Bevel bob]

Interesting !, the end cap opening on the right is clearly bigger and is as i remembered it. and looking at the silencer brackets , I would say the silencer on the right is an orriginal 64 type and the one on the left is a later fitment ,probably from the same source and sold as suitable for 175 to 250 . Its Also possible that different silencers were supplied to the UK and USA ?. All i know is that my bike would not run well with the smaller one and now sports a Norton Cherroot with a 38 mm outlet , that just bolts on with slight alteration to the Norton bracket. You seem to be missing at least a couple more singles ? !!

[kaysystems]

Thanks - I'm away drom home right now, but I'll check mine when I get back. I purchased men as new old stock. Will be interesting to see what it is.

David

[Bevel bob]

30.5 mm sounds about right ,and the bracket of your restored silencer looks right too for an orriginal.