Hi All,
When I rebuilt my C15 I replaced the Megaphone "silencer" with a "standard" one because it was too loud. I avoided the Armours silencer because I read on-line that it was loud. I got one from Feked instead. It also seems really loud. Both are straight throughs. Does anybody make a silencer that is more like the original spec?
The bike is stock apart from having a lumpy (SS80) cam (because I couldn't find a standard cam that wasn't knackered) and a 1" Concentric Mk1 (to match the 1" but small valve head that I got off Ebay and because AMAL didn't seem to do the Monobloc in Ethanol friendly at the time) so I wouldn't expect it to be this loud (it's not "characterful" it's actually painful!).
The bike runs very nicely and revs quite freely so I don't think the carburation or timing are off.
Any thoughts?
Thanks
If you find someone who makes a reasonably quiet silencer let me know. My old Armours silencer appeared to be getting noisy. I bought a Fexed only a slight improvement. Looking in the end it appears that the perforated tube and sound proofing do not extend the length of the silencer.
I have the same problem with my B40. Original silencer gave a nice sound but was beyond repair.
One I bought of a seller on fleabay fitted and looked good but was very loud.
Bought one from Armours that didn't fit ( I had to make some new brackets and a small extension pipe) but sounded better. Told Armour of my fitting problems - never got back to me so wouldn't recommend or use again.
I've read about DB killers. A sort of perforated tube the you can insert on the exhaust somewhere.
Either into the silencer or in the exhaust pipe where it joins the silencer
I have no experience of them so can't offer an opinion but the look like they may offer a solution.
Got my Starfire exhaust from Feked, fitted perfectly and good quality. It is loud though. I get the occasional disapproving look from passers by. But plenty of approving comments from people too.
I've never peered inside an original silencer, but the one
I have is straight through but has perforated mesh in the fat part. Not sure if that's how they always were.
I got one of these to fit in the 'silencer' of my 1949 Matchless 500.
https://www.ebay.co.uk/itm/UNIVERSAL-MOTORBIKE-EXHAUST-SILENCER-INSERT-BAFFLE-1-3-4-x-8-44mm-DRAG-PIPE/252158984657?hash=item3ab5d8c1d1:g:C0kAAOSwkmVgM8~4
The silencer was a replacement of unknown origin fitted well before I got the bike. It had an unpleasantly harsh exhaust note unbefitting a gentleman's mount. Whilst it hasnt made the exhaust eerily quiet, it has certainly got rid of the piercing bark it had and is no longer a source of embarassment. The shorter one isnt as effective, unsuprisingly, as Ive fitted one of those in the high level exhaust of my AJS 350 trials bike. The next plan is to stick a couple of stainless steel pan scourers in the shorty silencer ;)
Steve
I tried a short db killer on the loud B40 silencer - total waste of money ( albeit a couple of quid).
The idea behind the perforated tube is that it is wrapped with a glass fibre mat. Exhaust pulses (noise) go through the holes in the tube and vibrate the strands, creating friction. The energy absorbed by the strands is dissipated as heat; it's known as an absorption baffle. It has the advantage of being better at reducing high frequency noise, so you end up with a deeper, quieter exhaust note.
Years ago I had a bike with an absorption baffle. It seemed to be getting noisier, so as an experiment I removed the baffle and the little bit of glass fibre that remained on it, and rode round the block. It was no louder without the baffle, so I got some glass fibre and repacked it. The result was a quieter bike. Some sort of soft iron wire is ideal for securing the mat to the baffle.
Here's an example of the glass fibre mat; I haven't bought it myself.
https://www.ebay.co.uk/itm/Exhaust-Silencer-Wadding-340mm-x-550mm-E-Glass-Fibre-Packing-for-Motorcycle-UK/363336662241?hash=item54988d7ce1:g:T9YAAOSw0w5esRT1 (https://www.ebay.co.uk/itm/Exhaust-Silencer-Wadding-340mm-x-550mm-E-Glass-Fibre-Packing-for-Motorcycle-UK/363336662241?hash=item54988d7ce1:g:T9YAAOSw0w5esRT1)
It probably goes without saying, but if you use the glass fibre then wear gloves. I made the mistake a few years ago of not doing so. Not so bad when you're using it but later on in the evening it got a bit prickly and quite unbearable.
I've also used an oil free steel wool for exhaust packing. I can't remember if I just used it round the perforated core and then the glass fibre.
Quote from: Rog1 on 31 Mar, 2021, 13:55
The idea behind the perforated tube is that it is wrapped with a glass fibre mat. Exhaust pulses (noise) go through the holes in the tube and vibrate the strands, creating friction. The energy absorbed by the strands is dissipated as heat; it's known as an absorption baffle. It has the advantage of being better at reducing high frequency noise, so you end up with a deeper, quieter exhaust n
The 'db killer' isnt an absorption baffle, it simply provides a more tortuous route for the exhaust gas to follow. If you wrap it in matting all youll do is stangle the engine.
Steve
feked make baffles to fit inside of silencers https://www.feked.com/silencer-baffle.html
The feked one is the same as the cheap one bought from fleabay. Didn't work
I have no answer but the same question for my B40 Star. Hundreds of damned noisy bikers riding past today, so I've just come in to find I'm not alone on this one. Couple of unseen old singles went past my hedge and they were much quieter than mine.
I had heard that originally the silences may be better. Mine has caused an quite fruity and graphic argument with the neighbour & I daren't go out during lambing time for risk of having to foster a flock's worth of premature births.
I'll watch out for answers.
"Unbefitting a gentleman's mount." Yesterday I shared this phrase with a couple of my uncouth motorcycle pals here in the US.
I think we all have someone on our streets that doesn't like the noise our bikes make, I have one! and told her where to get off. I can't help with a silencer but a light hearted story might help.
It snowed last night...
8:00 am: I made a snowman.
8:10 - A feminist passed by and asked me why I didn't make a snow woman.
8:15 - So, I made a snow woman.
8:17 - My feminist neighbour complained about the snow woman's voluptuous chest saying it objectified snow women everywhere.
8:20 - The gay couple living nearby threw a hissy fit and moaned it could have been two snow men instead.
8:22 - The transgender man..women...person asked why I didn't just make one snow person with detachable parts.
8:25 - The vegans at the end of the lane complained about the carrot nose, as veggies are food and not to decorate snow figures with.
8:28 - I was being called a racist because the snow couple is white.
8:31 - The middle eastern gent across the road demanded the snow woman be covered up .
8:40 - The Police arrived saying someone had been offended.
8:42 - The feminist neighbour complained again that the broomstick of the snow woman needed to be removed because it depicted women in a domestic role.
8:43 - The council equality officer arrived and threatened me with eviction.
8:45 - TV news crew from BBC showed up. I was asked if I know the difference between snowmen and snow-women? I replied "Snowballs" and am now called a sexist.
9:00 - I was on the News as a suspected terrorist, racist, homophobe sensibility offender, bent on stirring up trouble during difficult weather.
9:10 - I was asked if I have any accomplices. My children were taken by social services.
9:29 - Far left protesters offended by everything marched down the street demanding for me to be arrested.
By noon it all melted and I had a ride on my BSA B31, found a note through the letter box when I got back, "can you be a bit more quite when starting that bike"
Moral:
There is no moral to this story. It is what we have become, all because of snowflakes.
Hahaha!
I'm no snowflake. Just don't like loud noise, like a large proportion of people trying to enjoy their homes. My neighbour asked why my bike was so noisy (amongst other comments) and I don't think that part of the conversation was unreasonable minded that I've heard other British singles passing that seemed considerably quieter. If it's technically possible to baffle the noise better without a great reduction in power/ fuel economy then it seems quite reasonable to do it for the neighbours/others benefit ( and I'd be grateful for those who opted for a quieter exhaust when they ride past my place)
I still remember going on a club ride with, amongst many other BSA's, 3 C15's - all were noisy but the one I was behind was biblically noisy especially under load, it was unbearable to the extent that I dropped right back, I could still hear it from half a mile away. The owner, a pleasant bloke, seemed unaware of the disruptive effect of the noise emanating from his bike and even when the fact was relayed to him by several other riders remained pleasant but regrettably unresponsive. He did mention later on when stopped that it was a stock silencer. I suppose that being at the opposite end of the bike to the exhaust pipe and moving away from it, so to speak, may have led him to believe that it was just a pleasant burble!
Hi,
Although a deviation from standard a short slash cut 90ยบ chrome tail pipe will help. When I had an outfit the exhaust was discolouring my pannier so I fitted one to deflect the exhaust down wards. It protected the pannier and reduced the noise from the exhaust.
Dave.
Hi all, thanks for the useful comments.
I was worried that a dB killer might just strangle the bike. I like the idea of the slash pipe though.
I have improved things a bit by resealing the pipe to silencer connection and I re-checked the ignition timing after I realised I had forgotten to correct the TDC gauge reading by allowing for the spark-plug hole being at 35 degrees. This requires you to dig out your cosine formula and it turns 7.14 mm before top dead centre into 8.72 gauge mm before top dead centre (please do the maths yourself but essentially it is 1.22 x nominal BTDC). Setting the ignition using this formula gave better top end performance and seemed to quieten it down a bit.
I would still like it to be quieter so I might try the slash pipe idea.
Thanks
You can fit vw beetle tailpipes if the silencer centre hole is large enough. Quite a few people used to use just them on there own in the end of bonnie downpipes.
:) :) :)
Brilliant.
Silencing: - Get about a sq ft of 1/2" Netting wire. Roll it up tube shaped and jam it up the pipe. It should cut yer noise down but it may also slightly affect performance. Its what I used to do before I could think of affording a new silencer. Or maybe before I could think.
Mike 8) 8) 8)
Why would you
Sorry - I didn't realise it was you who wanted a quieter machine and not the snowflake down the road. Unfortunately the C15's are probably one of the louder singles around. If it was me yellow foam ear plugs would be the best bet ;)
Does anyone make a quiet silencer at all.
The C15 green laner I had last year had a baffle but to be honest you couldn't tell the difference in or out.
https://www.classicbikeshop.co.uk/25mm-o-d-silencer-mute.html
Have a look at VW beetle silencer tubes.