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Blackcap mufflers and balancepipes for more torque #749936
09/21/18 2:50 am
09/21/18 2:50 am
Joined: Aug 2001
Posts: 2,556
Oztralia
R
Rohan Offline OP
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Rohan  Offline OP
BritBike Forum member
R

Joined: Aug 2001
Posts: 2,556
Oztralia
My attention has been drawn to an article that appeared in Classic Bike Guide for Feb 2012.
https://covers.magazinecloner.com/covers/37920/mid/0000.jpg
Norton Blackcap Silencer - the inside story.

Brian Dolman worked for NVT on developing/ improving the black cap mufflers, and details the stuff they did to test and improve them.
Significantly, he mentions the best results were with a balance pipe in the exhaust system and a distance of 28 inches from the port
seems to have given the best results - improving both the low end and higher rpms torque, as well as keeping a healthy midrange.
That would place it somehere about under the gearbox, the actual pipe isn't shown, or how they achieved that.
A little hand drawn dyno chart shows the results though, 55 bhp (engine hp presumeably). Quite healthy for a Mk 3.
And reports that by then, management weren't interested....

The 1st part of the article was Oct 2011, anyone got this issue ?
Or seen the discussion.

Hmmm, my guzzi has a balance pipe in the zorst under the gearbox, wonder where Brian went to work after NVT ?

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Re: Blackcap mufflers and balancepipes for more torque [Re: Rohan] #751141
10/01/18 9:04 pm
10/01/18 9:04 pm
Joined: Aug 2001
Posts: 2,556
Oztralia
R
Rohan Offline OP
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Rohan  Offline OP
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R

Joined: Aug 2001
Posts: 2,556
Oztralia
John Favill, formerly of Villiers was part of the orginal crew put together by Mr Poore to come up with the Commando
Speaking of working after NVT, it seems that John was Brians boss, and John then went on to work at HD.
Working on new engine designs for them, which culminated in the Evo engines of 1984.
A 7 year program.

Wonder how long it took to get the Norton design out to 850 (828cc) from the previous 745cc.
There is no written account of this (?), but it seems like it may have been only months,
after the Combat saga pushed the need for improvements.
Not a whole new design of course....


Moderated by  Dave Comeau 

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