PT: Exhaust Comet silencer

Mike 40M

Well Known and Active Forum User
VOC Member
As snow covers everything, the Comet will stay inside and get some maintenace. Some parts needed from the Spares Company.
I've read a couple of threads, about silencers, but still at a loss. I understand that the Campbell silencer should go to recycling ASAP.
Checked on the webshop and found there is a choise between an absorbtion and a spiral baffle silencer. Please give me some advice on which to choose.
Is their absorbtion type possible to repack easily? Opinions on performance and sound levels?
I'm not especially keen on high noise levels, has already bad hearing inflicted by race bikes.
 

Michael Vane-Hunt

Well Known and Active Forum User
VOC Member
The spares spiral silencer on my Comet, (8:1) is almost uncomfortably loud. The spiral silencer on my twin decreased my mileage significantly, so my old Kemp silencer went back on the twin
 

Marcus Bowden

VOC Hon. Overseas Representative
VOC Member
{{Is their absorption type possible to repack easily? Opinions on performance and sound levels?
I'm not especially keen on high noise levels.}}

I should not think so being an all welded fabrication, I made ten silencers on board ship many years ago now from a redundant S.W. pipe with s/s inlet stub screwed into a bronze flange 1+7/8" x 20 tpi, then the flange into what looks like brass pipe but in fact Yolcalbro (sea water resistant brass) with 20 tpi . With a 50mm diameter perforated s/s tube the length of silencer another bronze flange and a 2"tail pipe silver soldered into end flange. tried various packing material and the s/s pan scowers last the longest , silencer wadding is the quietest and a deeper note, I did hear that testing the various silencers on a dyno the absorption type produced more power (less restrictive !) About twice the weight to a normal silencer, but then made to last a life time , my second hand exhaust pipes I bought in mid 60's still polishes up like new why people like the shiny bling of chrome that eventually rusts I'll never know.
MSVH Y3 you are a bit far away to nip across to my place with the appropriate materials but there are several in you location handy with a daddy of all machines the LATHE.
bananaman.
 

vibrac

Well Known and Active Forum User
VOC Member
My last attempt on the Flash to get down to 105 Db for P6 parades at BHR meetings and still look age related I used a 2inch perforated pipe inside a 3inch alloy tube with 1/4" walls. Packing the 1/4 annulus with fibre packing and the ends were turned from solid ally again with 1/4" walls, the idea being that thin walls transmit sounds. I got about 104 Db and it passed.
Nowadays I dont bother with BHR as we cant race the Vincent Comet there so I am dammed if I will bother to parade with them. and I have found that at the events like Kop Hill and Bicester they actually enjoy the noise of a straight through 2" and why not?
 

erik

Well Known and Active Forum User
VOC Member
i have bought both silencers from the spares Company.first the straight through ,but it was to loud and then the spiral bafle which is okey.the one which came with the bike was to loud ,too.i have the standart copression Ratio,andit is very important what you have ,because more compression ,more noise.regards Erik
 

Mike 40M

Well Known and Active Forum User
VOC Member
Almost a year since I asked for advice.
Bought the spiral baffle one from the spares company.
Finally put it on the Comet yesterday. Not surprisingly had to make some fittings.
I did a 40 miles test run today. Conclusion:
Indeed a lot louder than the Campbell, but top speed increased 20 km/h ( 12Mph ).
Thanks for your advice.
 

Matty

Well Known and Active Forum User
VOC Member
I tried the club spares silencer which was very loud and rusted they gave me my money back and also the Armours one which I think was better quality and cheaper but also very loud.
I am presently using an old silencer which the baffles blew out of 25 years ago which is loud but OK.
The loud Armours one went to a friend with a Rapids where it was acceptably quieter, no doubt due to the big engine only having to work half as hard, also the resonances in the twin arrangement would be different.
There
Matty is a lot of stuff on the forum about this some years ago when I was trying to find a good silencer for my comet but no conclusions were reached.
I have owned my Comet since 1956 and it is very reliable and used Summer and Winter though now only about 3000 miles a year.
 

Bill Thomas

Well Known and Active Forum User
VOC Member
Yes Matty, I had a gutted Silencer on my Twin, Which was not too bad, But I put in on my Comet,
And it was too loud, Even for me !, The Bikes are not the same. Cheers Bill.
 

Matty

Well Known and Active Forum User
VOC Member
Sorry the text got a bit garbled near the end of my last note.
But if any one has found a good quality comparatively cheap , say less than £200 silencer for a Comet I would be most interested.
Matty
 

Bill Thomas

Well Known and Active Forum User
VOC Member
Sorry the text got a bit garbled near the end of my last note.
But if any one has found a good quality comparatively cheap , say less than £200 silencer for a Comet I would be most interested.
Matty
Hello Matty, Are you wanting brand new ?.
You say your Bike is an every day Bike, I have an old burgess, With a bit of chrome flaking off,
Don't know how much noise it makes , Have no clue if I have ever used it, But it has Baffles.
If it any good to you, Do you or your friends ever get down near Ringwood,
I can't see me ever using it, But don't want to throw it in the Skip !. Cheers Bill.
 

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