silencers

volvo850 · Post by **volvo850** » Thu May 24, 2007 12:16 am

My 1951 model 18 has a pattern exhaust system which fits ok , has good chrome, only problem is that it is very noisey! I mean LOUD.
OK, when we were young that was perhaps what we all wanted, but now I would quite happily pay for an effective silencer.
On my G80 in the 60's I had a Burgess silencer for a while and it gave a nice refined note.
Anyone out there had any experience of effective silencers or any advice
thanks

volvo850

jonhal · Post by **jonhal** » Thu May 24, 2007 8:58 am

jonhal · Post by **jonhal** » Thu May 24, 2007 9:03 am

Hi,
the pattern silencer on my G80 was the same. You can fit extra baffles from F2 Motorcycles Banbury. www.f2motorcycles.ltd.uk
Only about £11 inc pp. Works a treat, can be fitted either end of silencer.
Regards,
John

Don Madden · Post by **Don Madden** » Thu May 24, 2007 8:51 pm

AMC had a unique design on their road exaust systems.

The pipes were sealed at the end with a welded on cap. The pipes were perforated with holes or slots to allow gases to escape into a chamber of the silencer.

From the first chamber, the gases passed through vents into another chamber, then out the exit.

Without the sealed end on the pipe, the loud stuff goes straight out without baffling.

Conversely, I am told current UK regulations require all silencers sold for road use to have baffles. Using a baffled silencer on a pipe with the sealed end severely restricts exhaust flow.
This would account for the problems some have fitting a new silencer on an old pipe.

I got through this without sayin "muffler"--Oops!

Cheers, Don.

Biscuit · Post by **Biscuit** » Fri May 25, 2007 12:08 am

Those people, apparently unmentionable, down Bournemouth way, sell mutes or, colloquially, pepper pots that sit in the end of the pipe and mimic the closed end and drilled holes.

I'm intrigued, Don, how you manage to avoid words ending in 'our'

CR · Post by CR » Fri May 25, 2007 12:42 am

I have on occasions 'muted' a pipe by cutting two large slots (about 3/4 inch wide x 2 inches long) up the sides of the pipe (the part that protrudes into the silencer) and then spot welding an old twin inlet valve (or any other that would fit) into the open end of the pipe. The old valve simply acts to take out the combustion shockwave and significantly reduces the bark of a standard unbaffled silencer. I know that this sounds a bit Heath-Robinson - but it works perfectly and costs nothing.

Don Madden · Post by **Don Madden** » Sat May 26, 2007 4:54 am

Hello, Alan. It must have something to do with living with an Englishwoman for close to 50 years. When she was a translator for an American contractor in Brazil, (where we met), she had a State Department manual, (English Expressions not to be used in American Correspondence).

I suspect the job of translating the meaning of American words was more difficult than of Portuguese. Lots of fun, though with our "Common Language". Apolgies to GBS, but he was Irish, anyway.

Cheers, Don.

Eric · Post by **Eric** » Sat May 26, 2007 6:01 pm

The advice about blanking the end of the pipe and then adding holes or slots into the pipe are correct. Make sure the area of all of the holes or slots is greater than the bore of the pipe. From memory I think its four rows of 4 holes each 7/16" dia so each row can be positioned in the the relevant quarter of the pipe and spread over a length of about 4". The holes in each row should ideally be offset to the adjacent row.

itma · Post by **itma** » Sat May 26, 2007 6:47 pm

A baffle like any of the above also has other effects
I once had a SV Norton that was a pig to start and which was markedly improved after a baffle was fitted, something to do with back pressure,.