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
Decibels from a hot Comet
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="Tom Gaynor" data-source="post: 13552" data-attributes="member: 4034"><p><strong>Nobby's Comet</strong></p><p></p><p>No need to take Nobby's word for it. He only lives in Holland. Get him to start it up, and if the wind is in the right direction, you can hear it for yourself. From Britain. After his visit to Applecross, Highland A & E departments were choked with sheep complaining of sudden inexplicable deafness. Honest.</p><p></p><p>So far as the motor and its gas dynamics are concerned, the start of the megaphone is a change of section. The mega exit is another. At each change of section a reverse pressure wave is sent BACK the way it came. A positive pressure pulse OUT becomes a negative pressure wave IN, timed to suck fresh mixture down the exhaust tract, and the following positive wave crams it back into the pot just as the valves close. Result? Supercharging. This was Walter Kaaden (of MZ)'s great discovery. It's rather more complicated than that, but essentially what Peter V has been doing is getting the timing of the resonant system that is his Rapide, right. That and leaning it over until his ears touch down.</p><p>Most of the fastest modern classic Manxes and G50's have a pipe that tapers all the way from the exhaust port to the end of the pipe, from 1 5/8" at the port to about 3" at the exit. I don't know how that works, but judging by the speed at which they clear off, it does. </p><p>The best book on the subject is Graham Bell's Four-Stroke Performance Tuning. He also deals with two-into-one (Vincent...), as well as four-into-two-into-one, eight-into... but you get the picture.</p><p>TFS is rather outdated.</p><p></p><p>Tom</p></blockquote><p></p>
[QUOTE="Tom Gaynor, post: 13552, member: 4034"] [b]Nobby's Comet[/b] No need to take Nobby's word for it. He only lives in Holland. Get him to start it up, and if the wind is in the right direction, you can hear it for yourself. From Britain. After his visit to Applecross, Highland A & E departments were choked with sheep complaining of sudden inexplicable deafness. Honest. So far as the motor and its gas dynamics are concerned, the start of the megaphone is a change of section. The mega exit is another. At each change of section a reverse pressure wave is sent BACK the way it came. A positive pressure pulse OUT becomes a negative pressure wave IN, timed to suck fresh mixture down the exhaust tract, and the following positive wave crams it back into the pot just as the valves close. Result? Supercharging. This was Walter Kaaden (of MZ)'s great discovery. It's rather more complicated than that, but essentially what Peter V has been doing is getting the timing of the resonant system that is his Rapide, right. That and leaning it over until his ears touch down. Most of the fastest modern classic Manxes and G50's have a pipe that tapers all the way from the exhaust port to the end of the pipe, from 1 5/8" at the port to about 3" at the exit. I don't know how that works, but judging by the speed at which they clear off, it does. The best book on the subject is Graham Bell's Four-Stroke Performance Tuning. He also deals with two-into-one (Vincent...), as well as four-into-two-into-one, eight-into... but you get the picture. TFS is rather outdated. Tom [/QUOTE]
Insert quotes…
Verification
What was Mr Irving's Christian Name?
Post reply
Home
Forums
Forums: Public Access
Tech. Advice: Series 'B' / 'C' 500cc/1000cc Bikes
Decibels from a hot Comet
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