Dunstall Decibel Silencer Baffles

My MkIII is fitted with original Dunstall “silencers” that have been on the bike since I purchased it from the original owner in 1978. I understand that there were different versions. Mine are a straight through design with a 1” diameter or so punched metal tube runninng the full length that is removable. This tube has a punched metal baffle welded in about half way. The exit is the “Gatling gun” arrangement with a central solid rod in the center with a threaded hole and extending past the discharge tubes. The aft end of the exhaust is cylindrical w/o reverse taper. I have read some comments that the Dunstalls are quieter than pea shooters. They are not referring to my bike...

I’ve read that there was a baffle available from Dunstall to quiet them down. I assume that this would be a washer type piece that would be attached out past the Gatling barrels to partially disturb the exiting gas flow. Does anybody know the OEM part size(s) and looked like? Could wrap mineral wool around the internal pipe but I that would likely negatively affect performance more than baffle. Ideas/experience?

Thanks.

Dave

Re; "My MkIII is fitted with original Dunstall “silencers” that have been on the bike since I purchased it from the original owner in 1978. I understand that there were different versions. Mine are a straight through design with a 1” diameter or so punched metal tube runninng the full length that is removable."

I’m no expert on the Dunstall decibels , (without the end cone) but as follows ; early ones have the centre mounted baffles bolted on by three bolts. Later, probably copies, were attached with pop rivets.

The wraparound mineral wool was on the interior of all silencers, as far as I know, but this got burnt/worn and blew out with the exhaust gases , fitting new mineral wool to retain the quietness was not uncommon. No idea about the other questions asked, but look at the washer welded here;


https://www.accessnorton.com/NortonCommando/dunstall-silencers.16311/#post-236815

also the following others on this website;

https://www.accessnorton.com/search/1636125/?q=Dunstall+decibels&o=relevance

Mon Jul 16 20:09:55 PDT 2018


Dave,

The description you provided of your Dunstall silencers could apply to more than one of the many designs of Dunstall silencers that there were. But here's a short video that may provide you with the information you're looking for:


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My description was for the EARLY Decibels, the many latter ones available had subtle differences.

Thanks for the video, the Dunstall box in the background is when he registered his company as the P.D. Organisation, so he would have been in his new shop.

Those end caps looks like a restrictive mod, so, most people would remove them . . . or they fell off!