Silence is golden

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robint
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Silence is golden

So Mowers from a 1/2" bsp flange to the ultimate Whisper Muffler straight from a trash can.  The connector is Wickes 15mm tank connector £3.  Notice the handy slow bend £2.85.  The secret to its success is the filling of Rockwool and super acoustic pugging.  I reckon this will do 5 years.  It will get a protective coat of exhaust silver paint but its humble origins still shine.  Of course it will be easy to replace the can when it gets shouty

Beats a BnS can for £13

I hope to post a video to show how much quieter a Whisper Muffler is.  BTW most modern (nasty) rotary rubbish boast 90dB.  I will see what mine does.  Ive got a Mountfield (wash my mouth out) to make a comparison

Chris G
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Haha, good one. Don't pack it

Haha, good one. Don't pack it too much or it won't breath!

Had to buy a decent sound level meter a while back as working on a drag bike, and even those tracks have rules!

For ref, my Marquis is at 75dBA tickover and 85dBA full chat - level taken from the handle bar. This is my Marquis at tickover just now

https://youtu.be/lVJrTWuiKP8

My Mountfield and Suffolk punch are both a lot louder 

One thing needed to be understood in dB numbers is that once you get to a certain level the smaller increase in the numbers are massively magnified in what a person actually hears so from my measurements 75-85 its about 3 times louder to the human ear - this chart explains it a bit

 

robint
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Yes indeed, thanx for added

Yes indeed, thanx for added info and to explain about dB without getting all logarithmic.

That you tube clip is instructive and just shows what we take for granted - noisy lawn mowers.

I had a Honda elite 125 scooter for a while.  Nice little machine EFI and automatic gears.  Amazing how heavy it was, but the real thing is that it was incredibly quiet, so much so that pedestrians wouldnt hear me coming along

with my slow bend I will be able to experiment with different sized cans and internals.  I am really surprised the mower industry hasnt addressed this issue. neighbours can be upset by noisy mowers

Should I repurpose a coke can?  SS thermos flask?  https://www.wilko.com/en-uk/wilko-vacuum-flask-stainless-steel-1l/p/0250417

https://www.wilko.com/en-uk/wilko-double-wall-flask-steel-500ml/p/0465725

they would be practically everlasting, well into the next century (well my current Marquesa has lasted nearly 60 years - its a humbling thought like a 200 year old galapagos turtle still wandering around)

My Android Notepad has an app that measures dB using the internal mike.  It works

Will post progress

 

wristpin
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The ” mower industry” did

The ” mower industry” did address the issue in 1989 ( I think) when the new regs came out. They reduced the rpm of most rotary machines from an average of 3300 to 2800 at which point neither walk behinds nor ride ons would fill their grass bags. So almost before the ink was dry on the regs we all received Service Bulletins explaining that the regs only applied at the point of shipping and that we should all increase the rpm back to 3000.

zThen they started drilling holes in the air lifts on rotary blades.......  I digress!

Interestingly , in a similar manner to the majority of noise from HGVs ( sorry LGVs)  comes from tyres and cooling fans , the majority from cylinder mowers comes from badly set blades and drive chains. Engine noise reduction is relatively easy to deal with, blade and transmission noise, not so easy.

 

NM
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Joined: 31/05/2018 - 15:09
Noise is usually always worse

Noise is usually always worse when It’s someone else’s and at an inconvenient time. Drag racing noise regs used to be unheard of, open headers galore.

robint
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Well mower racket is real

Well mower racket is real when you cant have a conversation with an adjacent person when the mower is revved up. Mowers cant go into denial when 7.5 litre RR phantoms whispered along the highway.  I think 2st rotaries got way too macho and fueled on testosterone.  Think of one foot in the grave

 

heh heh

I want to demonstrate the quietest ever cylinder mower.  Didnt the super auto ceres introduce a micro adjustable cylinder height so that it barely licked the lower blade by a thou?

Special widget to stop the roller drums clanking cheeks together

Acoustic hood over the engine?

perhaps it will stop raining

robint
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Just when you thought it

Just when you thought it couldnt get any better - Just fitted the everlasting super-pugger whisper muffler

May have some fertling to do, waiting for my acoustic ingredient to arrive, then will make some videos.  The can is made from an old Wilko 1/2L SS thermos flask - £5. Should last indefinitely as its 316 not 304.  It should purr not bark  Way to go

Merry mowing

Chris G
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You're not serious are you?

You're not serious are you? That looks like its going to strain the ali exhaust port holes over time hanging off that.

It also looks like a bottle of nitros. If it is its plumbed to the wrong port.

 

robint
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Joined: 19/07/2018 - 15:46
Now there's a thought - a

Now there's a thought - a nitrox kit

Ive got some more plumbing bits on order and a tiewrap should give it a bit of surgical truss

Now if I got a bit of platinum plated  steel wool it would then be a green friendly mower with a low carbon roller print

go think outside the exhaust can

robint
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I missed out on this petrol

I missed out on this petrol Petter PA2 when I went to collect my Lister D type

It would have benefitted from my Super Pugger Whisper Muffler. The acoustic nodules arrived today

Kerriste it was noisy compared to the Lister with its 1.5 bhp from 600cc @750rpm

https://www.youtube.com/watch?v=HKsEp0_gcG8

Ive got the latest super smooth racing muffler on order

 

I want to make use of the double wall construction so gas flows through a labyrinth

they did that on bikes

http://www.classicbikepartscheshire.com/exhaust-parts-c52/silencers-c179...