Silencer Construction, for Plunger A10

[MikPowl]

Chaps, Does anyone know exactly what the baffles inside an A10 silencer actually look like?  The reason for asking is that I'll soon (within the next 5 years!) be needing a pair of silencers for my plunger S/Flash A10 project. Bought many years ago, I have a pair of genuine Burgess silencers whose guts have more or less taken leave of absence as rust particles. My plan was to get rid of all traces of baffle, clean up the silencer cans and get them plated. Then I thought maybe a length of perforated 1-1/2" s/steel pipe pushed through from one end to the other and attached somehow or other would provide at least some baffling. I'm happy for a more outspoken tone than standard but don't want to be outrageously loud, and then there's the question of sufficient back pressure. Any thoughts?

[JulianS]

Below from David Munro's book "BSA Twin Motor Cycles"

[Bsareg]

I've tried that perforated 1.5" tubing on my 29 200cc Fanny B. Welded cap halfway down in the hope the gases would be forced outwards and then back in to exit. It didn't work and was bl##dy noisy. Think I should have put some wadding around it but too late as all welded. Ended up stuffing pot scourers up the end to make to the noise acceptable. They can be hooked out when they become blocked.

[MikPowl]

Wah! It's surprising that any gas at all gets past that baffle defence system. Think I'll need to rethink this, but it would be good to use the old Burgess cans. I remember they were famous for pioneering 'straight through' exhausts on cars. These seem to have been made for the A10 but weren't a standard fitting, i don't think.  Any other info/ideas would be gratfully received! 

Also, any S/F owners out there - what was the difference between the S/F exhausts and the standard plunger items - pipes and silencers have different part numbers?

[Joolstacho]

That's a complex little arrangement ain't it? I wonder how the Goldie silencer compares.

[Black Sheep]

In the absence of baffles, I use 1cm galvanised square mesh rolled tightly round a broom handle and pushed into the silencer. It tries to unwind which anchors it pretty firmly in there. Cheap and simple.

[Rex]

I used one of those cheap Ebay kits where you get a large square of wadding and some stainless tie-wraps, and wrapped it around a piece of perforated ally sheet which was rolled around some bar to get the shape.
Waste of money...

[bikerjohndavies]

This may not be of help but the original Super Flash exhaust down pipes looked like this and the silencer had no baffles in it. You could possibly do something similar?

[limeyrob]

Forget back pressure, its a myth. If there's better exhaust flow and its breathing better you may have to up the jet one size.  Those Burgess silences were quite restrictive and the whole lot ends up as a pile washers in one end.  I got perf steel, rolled it and packed it with Brillo pads...don't, wire wool burns
What does work is to make a tube out of perf steel, make it long and a good fit, then weld a big washer in it half way down.  Fix it with a bolt in the tail pipe underneath.

[Bsareg]

That sounds similar to the scheme I used but I used stainless pot scourers, no burning yet.🤞

[groily]

When after a semi-friendly discussion with a gendarme I was encouraged to do something 'right now if not sooner' to quieten an amplifier (see pic), I turned up a disc of 13mm alloy plate, drilled a pretty pattern of holes through it, chamfered it a tad on the circumference to match the taper of the cone, and rammed it up the end until it was well stuck. Then used three radially-disposed ss screws to locate the 'baffle' by drilling and tapping through into the ali.
Reduced the noise by quite a bit. No changes to jetting have seemed necessary (it's on a 450 main already, that one).

So I like Rob's suggestion  - and the Super Flash pipe design too (which was also used by some other marques back when).
Anything to avoid shelling out big bucks for replica shiny stuff of often doubtful provenance, especially on bikes that are out and about all year round.

[limeyrob]

I seem to recall those Burgess silencers are really thick steel so they are good basis for a home made solution.  I doubt you will find anything as solid being sold now.

[groily]

I seem to recall those Burgess silencers are really thick steel so they are good basis for a home made solution.  I doubt you will find anything as solid being sold now.

Very long lasting too Rob! Here's a 70-yr old one (different shape compared to Beesas but same quality materials, complete with a bit of a bandage poor thing) still in daily use  . . .

[MikPowl]

Some really useful stuff here - Thanks!  And BikerJohn has solved the mystery of what was different about SF pipes and silencers - that looks like the answer to my query. One more Q for BikerJohn - why does the pipe appear to change size towards the perforated section - is it actually one pipe, or two pipes joined?  And does the 'bend' look standard Gold Flash or is it difficult to say?  (Sorry, that's 2 q's). It might be worth asking Armours to bend me pipes with extra long tails which can be perforated and will fit straight thro the Burgess bottles.  Getting there!

[Joolstacho]

I haven't tried this, but I wonder if a Velocette front baffle might do the job. They're easily available new. It's simply a tube that slips over the end of the header pipe, and then clamps inside the front of the silencer section. It's about a foot long and has nicely shaped slots (vents? whaddaya call those things?) along and around it's length. -Just an idea.