The Spares Company
Club Shop/Regalia
Parent Website
Contact Officials
Machine Registrar
Club Secretary
Membership Secretaries
MPH Editor and Forum Administrator.
Section Newsletters
Technical Databases
Photos
Home
What's new
Latest activity
Forums
New posts
What's new
New posts
Latest activity
Information
Bike Modifications
Machine Data Services
Manufacturers Manuals
Spare Parts Listings
Technical Diagrams
Whitakerpedia (Vincent Wiki)
The Club
MPH Material Archive
Flogger's Corner
Obituaries
VOC Sections
Local Sections
Local Section Newsletters
Miscellaneous
Club Assets
Club History
Club Rules
Machine Data Services
Meeting Documents
Miscellaneous
Essential Reading
Magazine/Newspaper Articles/Letters
Adverts and Sales Brochures
The Mighty Garage Videos
Bikes For Sale (Spares Company)
Log in
Register
What's new
New posts
Menu
Log in
Register
Install the app
Install
Home
Forums
Forums: Public Access
Tech. Advice: Series 'B' / 'C' 500cc/1000cc Bikes
600cc Comet Carbie?
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="vibrac" data-source="post: 77547" data-attributes="member: 60"><p>Silencers and tests:</p><p>I was once volunteered as a noise tester at a race meeting, during testing a very very noisy NSU sports max came to be tested, we checked the stroke and found the correct revs the reading was to be taken at. The rider increased the revs the noise increased then as the correct measuring rev band came near all went quiet and at the measuring point it was legal at 105 Db. I of course asked the question and the rider showed me that under the crankcase at right angles to the main exhaust was a branch pipe sealed off with a brazed on disc. he had found by experiment just the length that cancelled out the sound waves. I belive <em><a href="https://www.google.co.uk/search?q=helmholtz+chamber&client=firefox-b&sa=X&biw=1280&bih=563&tbm=isch&tbo=u&source=univ&ved=0ahUKEwiwzq7c17DRAhVD7yYKHTCPBm4Q7AkIMg" target="_blank">helmholtz chamber </a></em><a href="https://www.google.co.uk/search?q=helmholtz+chamber&client=firefox-b&sa=X&biw=1280&bih=563&tbm=isch&tbo=u&source=univ&ved=0ahUKEwiwzq7c17DRAhVD7yYKHTCPBm4Q7AkIMg" target="_blank">is the key to further reading. If you cant join em beat them.</a></p></blockquote><p></p>
[QUOTE="vibrac, post: 77547, member: 60"] Silencers and tests: I was once volunteered as a noise tester at a race meeting, during testing a very very noisy NSU sports max came to be tested, we checked the stroke and found the correct revs the reading was to be taken at. The rider increased the revs the noise increased then as the correct measuring rev band came near all went quiet and at the measuring point it was legal at 105 Db. I of course asked the question and the rider showed me that under the crankcase at right angles to the main exhaust was a branch pipe sealed off with a brazed on disc. he had found by experiment just the length that cancelled out the sound waves. I belive [I][URL='https://www.google.co.uk/search?q=helmholtz+chamber&client=firefox-b&sa=X&biw=1280&bih=563&tbm=isch&tbo=u&source=univ&ved=0ahUKEwiwzq7c17DRAhVD7yYKHTCPBm4Q7AkIMg']helmholtz chamber [/URL][/I][URL='https://www.google.co.uk/search?q=helmholtz+chamber&client=firefox-b&sa=X&biw=1280&bih=563&tbm=isch&tbo=u&source=univ&ved=0ahUKEwiwzq7c17DRAhVD7yYKHTCPBm4Q7AkIMg']is the key to further reading. If you cant join em beat them.[/URL] [/QUOTE]
Insert quotes…
Verification
What was Mr Vincent's Christian Name?
Post reply
Home
Forums
Forums: Public Access
Tech. Advice: Series 'B' / 'C' 500cc/1000cc Bikes
600cc Comet Carbie?
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
Accept
Learn more…
Top