Original MK3 black cap silencers

elefantrider said:
What happened to the rest of the museum bike?
Click to expand...
The guy who purchased the bike, didn't like the black caps so changed them to peashooters, spoke to him and he is recommissioning it, brakes, calipers, the full works then he's going to use it, when I was there collecting the pipes the bike had 29 miles on the clock, basically brand new, but now not original.
 
jimbo said:
extremely unlikely any aftermarket bean cans are internally the same as the originals. look up Annular Discharge mufflers.

jimbo

Post in thread 'Black cap bean can modification'

I like my original Favill designed Annular Discharge Silencers, my MK3 goes just fine and is quiet. Be careful comparing the real ones to aftermarket they are built different.

Black cap bean can modification


View attachment 119599
Click to expand...
All done at Manchester University (fine place, can't speak highly enough of it :)).
What isn't widely appreciated is they improved performance over the peashooter.

Quote:
Back-to-back power tests were completed with Roe’s new silencer. It was found that the ‘annular discharge’ silencer gave a large boost in low speed torque. The net effect was an increase in power from 2000-4000rpm, a slight loss from 4000-5000rpm, and a gain above 5000rpm. The increase in low speed torque allowed the Norton to be fitted with a higher gear ratio, which also meant a reduction in noise due to the lower engine speed utilised during noise certification testing.

Original MK3 black cap silencers

I'm guessing the induction silencer is referring to those rubber caps fitted to the plastic airbox?
Removing them was always a no-brainer, and here's the evidence why.
 
B+Bogus said:
I'm guessing the induction silencer is referring to those rubber caps fitted to the plastic airbox?
Removing them was always a no-brainer, and here's the evidence why.
Click to expand...
None of the curves depict black cap production silencers w/o induction silencers, so where is the evidence?

It's my understanding that "standard equipment" means peashooters and hamcan air filter.

-Knut
 
mdt-son said:
None of the curves depict black cap production silencers w/o induction silencers, so where is the evidence?

It's my understanding that "standard equipment" means peashooters and hamcan air filter.

-Knut
Click to expand...
Guilty! I got it bass-ackwards :rolleyes:
 
It says 'Standard Silencers and induction silencer' I read that as Peashooters and the Blackbox. It does not say 'Standard Equipment' which is a meaningless anyway as when do they mean the standard applied.
 
The black caps are much of what makes a MK3, IMO. It is unfortunate for that change on a 29-mile bike.
Any pictures of that bike posted somewhere?
 
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L.A.B. said:
Image here.
jimbo

Post in thread '75 Commando Muffler Dilema'

I didn't realize your bike was so pristine. You should try to find correct original parts for it, when replacing anything on it . Just like your Hondas. There are plenty of hotrodded, modded ,upgraded ,whatever you call it,Norts out there ,(mine included!), but "theyareonlyoriginalonce"


here's a end of a "bean Can"
showing the correct markings and heres your bike and heres mine ( I do run a set of real MK111 muffs and I like them)

Note that Triumph T160 and Norton's black caps were not the same.
Original MK3 black cap silencers
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A friend of mine is in the finishing touches of his mk3 he’s had since he was 18. He swears by the black caps and air box but although these original silencers not copies have the correct part # there is no centre rivet.
Original MK3 black cap silencers
 
The rivet was only a temporary measure until as it says in the Norton Triumph bulletin 10/75 (Triple) that "Later mufflers are stamped with the appropriate part number for identification" which they both are.

And of course the black cap silencers were introduced on the 850 Mk1A so plenty of time for them to have changed to the stamping by 850 Mk3.

I'm surprised those apparently original black caps haven't rotted away.
 
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L.A.B. said:
The rivet was only a temporary measure until as it says in the Norton Triumph bulletin 10/75 (Triple) that "Later mufflers are stamped with the appropriate part number for identification" which they both are.

And of course the black cap silencers were introduced on the 850 Mk1A so plenty of time for them to have changed to the stamping by 850 Mk3.

I'm surprised those apparently original black caps haven't rotted away.
Click to expand...
The insides might be corroded, a person can take the mufflers and knock them on the floor to see how much rust comes out. Also the insides become loose and begin to rattle. If they were made to Favill's specifications and the internals made of stainless using the patents and computerized CNC components , they could have been much much better
 
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The bike has been in bits since 2008 and the silencers stored well. However I did tap one and there was some resonance but they sound fine running, if you like a quiet Commando that is 🤣 🤣 🤣

Honestly, I followed him on a short shakedown run and I could barely hear him although he wasn’t pushing it as the engine still needs running in since Normal White rebuilt it; one of the quietest 850 engines I’ve heard.
 

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