Author Topic: Villiers silencing question  (Read 613 times)

Offline iansoady

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Villiers silencing question
« on: August 06, 2020, 01:35:02 PM »
I've gone over to the dark side (again) and bought a 1955 Francis Barnett Cruiser with a Villers 1H engine. When I started it it made the most unholy racket so I had a look inside the "silencer" and found this:



On dismantling the silencer I found that the front pipe had a baffle tube attached to it. This has about 20 3/4" diameter holes in a sort of spiral pattern. The baffle is not blanked off at the rear end. The silencer tail pipe has a blanking disc in the end and a slit about 5" long x 1/4" wide on the underside of the tailpipe.

The baffle tube was virtually filled with what looks like fibreglass wadding to an extent that only the first couple of holes would allow any exhaust gas through. I take it that this had been added by a previous owner.

Can anyone confirm whether this looks like the correct baffle tube? I'm puzzled by the fact the tail end is unblanked as this would just let the gases straight through. Or am I missing something?

This is the bike:



Needs some TLC but will be ideal for pottering around the Worcestershire lanes when done.
Ian
1952 Norton ES21955
Francis Barnett Cruiser 75

Offline R

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Re: Villiers silencing question
« Reply #1 on: August 06, 2020, 10:31:05 PM »
Goodness, I started my (offroad) riding career on one of those.
But you got  lot of 'extras' I didn't - like mudguards, headlamp, muffler...
And even paint, half of it was in primer.  A DIY sort of purchase.

So I can't help with the muffler question, but I think you are on the right track saying the end of the pipe isn't blanked off.
Have you tried it without all the wadding ?
I've heard that stainless steel wool is quite good for that purpose, since it doesn't rust and won't catch fire.
But haven't actually tried it yet...

Offline 33d6

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Re: Villiers silencing question
« Reply #2 on: August 07, 2020, 06:30:40 AM »
Superficially the whole lot looks regular Francis Barnett but from the size, number and placement of holes in the inner pipe I suspect an aftermarket replacement or a PO with a 3/4" hole saw. Unfortunately few people appreciate that the internals of these old silencers have to be as factory made if you want them to work as when the bike was new. Repros may look the same but rarely sound the same. They are invariably too noisy.
The tail pipe slot needs to be the original size as well. 
I went down this same track with a '51 James and whilst looking for info came across a useful article with a clear drawing of the proper Francis Barnett internals for yours. It was on the British Two Stroke Club site where they had up sample pages of their Club magazine and this was one of the articles. Unfortunately this was ten years ago so I suspect they may have updated their site once or twice since then. No matter, I kept a copy and can send it to you if you wish. A direct copy straight from the BTSC website would be much clearer than a copy of a copy from me but that's up to you.
An internal rebuild should be bog easy as its just a matter of replacing the internal pipe having the right size holes in the right spot and checking that the outer barrel has the appropriate simple baffles.
Cheers,



 

Offline iansoady

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Re: Villiers silencing question
« Reply #3 on: August 07, 2020, 11:49:31 AM »
Ironically, I bought the bike from the dating officer of the BTSC....

Yes please to a copy of that page(s) as, as you suggest, that is no longer the sample on the website. Having joined the FBOC I'd prefer not to join the BTSC as well. I'll PM you if I can find out how to do it.....

I can't see any baffles etc in the outer casing. I suspect it's an Armours replacement (which to be fair is probably all that's available). I'll also have a chat with Villiers Services who've always been very helpful with brake relining etc.
Ian
1952 Norton ES21955
Francis Barnett Cruiser 75

Offline 33d6

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Re: Villiers silencing question
« Reply #4 on: August 07, 2020, 03:13:53 PM »
I couldnít resist checking out the BTSC site myself and also saw it has been updated since. I also read the current sample magazine displayed and found the author of the silencer article received condolences in it as he had recently been widowed. His name is John Hawthorn. He then held office in the Club so must be known to your seller. It might be more productive to get the info straight from the horse mouth so to speak.

Iím still happy to send a copy but I suspect tackling the author direct will be better.

Cheers,

Offline iansoady

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Re: Villiers silencing question
« Reply #5 on: August 07, 2020, 04:39:29 PM »
Thanks for that.

If you could let me have a copy of yours that's the way I'd prefer to go at the moment otherwise I may have to join yet another club!

I've just had a word with Villiers Services and they suggest that what I have is pretty much standard. I'm sure that removing the padding from inside the baffle tube will have helped to some extent and I may experiment with (a) blanking off the end of the baffle tube and (b) wrapping some expanded metal round it to slow the gases down a bit.

One of the FBOC forum lads gave me this (photo attached) which shows an entirely different arrangement folr a Greeves. I have to confess that 2 stroke silencers are a mystery to me and there doesn't seem to be a great deal of info about.

Ian
1952 Norton ES21955
Francis Barnett Cruiser 75

Offline 33d6

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Re: Villiers silencing question
« Reply #6 on: August 08, 2020, 07:25:01 AM »
My miserable computer skills have come to the fore. I have a problem with the two pages of silencer info I've scanned in that each is now a PDF file of over 1MB. How can I reduce them to get below the 6000KB per post?
Any advice will have to be at DUMMY 101 level.
Cheers,

Offline Rex

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Re: Villiers silencing question
« Reply #7 on: August 08, 2020, 08:47:34 AM »
I have a spare silencer which came with the Coventry Eagle, and that has the long slot down the side of the tail pipe though the tailpipe end is almost sealed with a large washer. Strange design.
Re the bike in the pic I'm always amazed at how many bikes have the rear brake light switch mounted in the strangest ways. On this bike the spring must almost move "to-and fro" rather than being pulled. Wouldn't a swinging arm mounting have worked better for whoever did it?
« Last Edit: August 08, 2020, 10:13:02 AM by Rex »

Offline iansoady

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Re: Villiers silencing question
« Reply #8 on: August 08, 2020, 10:09:03 AM »
Re the bike in the pic I'm always amazed at how many bikes have bikes rear brake light switch mounted in the strangest ways. On this bike the spring must almost move "to-and fro" rather than being pulled. Wouldn't a swinging arm mounting have worked better for whoever did it?

The original had quite an elegant "reverse operated" brake light switch (an optional extra of course). The one fitted is the usual universal type that fits nothing properly. I will endeavour to find and fit the proper thing.....
Ian
1952 Norton ES21955
Francis Barnett Cruiser 75

Offline iansoady

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Re: Villiers silencing question
« Reply #9 on: August 08, 2020, 10:10:09 AM »
My miserable computer skills have come to the fore. I have a problem with the two pages of silencer info I've scanned in that each is now a PDF file of over 1MB. How can I reduce them to get below the 6000KB per post?
Any advice will have to be at DUMMY 101 level.
Cheers,

Could you email them direct to me: ian at iansoady dot org dot uk (as mentioned in my PM to you)?
Ian
1952 Norton ES21955
Francis Barnett Cruiser 75

Offline R

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Re: Villiers silencing question
« Reply #10 on: August 08, 2020, 11:15:46 PM »
a PDF file of over 1MB. How can I reduce them to get below the 6000KB per post?

Wait a minute. !
6000KB is 6 Mb, so maybe there is no problem ?

Offline 33d6

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Re: Villiers silencing question
« Reply #11 on: August 09, 2020, 02:27:35 AM »
Email with attachments happily on its way Ian.

Offline iansoady

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Re: Villiers silencing question
« Reply #12 on: August 09, 2020, 11:09:12 AM »
Received loud & clear - many thanks Bob.
Ian
1952 Norton ES21955
Francis Barnett Cruiser 75

Offline R

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Re: Villiers silencing question
« Reply #13 on: August 09, 2020, 11:22:38 PM »
So now the rest of us are pondering what we have missed out on ?
And what won't be available to future readers.

I've got  mufflers with tubes that can poke into the can from both ends,
with the holes in them - so you can vary the % of influence.
Haven't quite got to try them yet, the engine isn't quite done ...

Offline 33d6

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Re: Villiers silencing question
« Reply #14 on: August 10, 2020, 05:29:45 AM »
I suspect Ian will be able to casually pop my information up without any bother. I really have no idea why it decided not to work for me but being a dinosaur from the mechanical age electrickery sometimes likes to lead me a merry dance.

For that matter I find two-stroke exhausts on road bikes an interesting subject. Racing exhausts seem to attract a lot of attention but are pretty useless for anything else. A road silencer that is both inoffensive and takes advantage of tuning knowledge is much more interesting.

Cheers,