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
New Amal Premier 900 series Carb for Comets
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="Martyn Goodwin" data-source="post: 46086" data-attributes="member: 2433"><p><strong>Amal Mk1 930/301PREM/A Carb for a Comet</strong></p><p></p><p>I installed a "new" Amal unit on my Comet some 2,000 miles back and it has transformed my bike. Easily starting , smooth idle and loads of power (when compared to the knackered old original unit It is a “improved” Amal Mk1 930/301PREM/A concentric. After consulting with Big Sid, I had it configured as follows; #3 Slide (hard anodised), 106 Needle Jet, 210 Main Jet, RJ19 Pilot, a Norton Commando style spray tube (which has the entire rear section –that faces the inlet valve – cut away), viton tipped float needle, “stay-up” float and a K&N air filter. I installed the new carb using a flange to flange stainless steel manifold I obtained from Jim Mosher in the USA. I profiled the inlet port opening on the head to provide a smooth gas flow thru the manifold and into the inlet port. I also installed a Bakelite heat insulator from a Norton, between the manifold and the carb. Taking note of the Amal instructions I used Nyloc nuts when securing the carb to the manifold and tightened them to just 4 foot pounds. At first I could not be happier with the result. </p><p></p><p>BUT <span style="font-size: 18px"><strong>WARNING </strong></span></p><p></p><p><strong>December 9, 2013 update:</strong>: After a long run of a 100 miles or so at high speed the motor was overheating to the extent the the pipes blued badly and I lost a fair bit of compression. Internal examination revealed an overheated and damaged piston, broken top ring etc - so it seems I was running way too lean. Additional trials are underway following a rebuild and I started out with a 250 main jet and the needle in the bottom grove ( rich setting). .</p><p></p><p></p><p><strong><span style="font-size: 12px">Current RECOMMENDATION , DEC 9, 2013</span></strong></p><p></p><p>After extensive road trials conducted over a number of weeks the following is the current suggested configuration for a Amal Mk1 Premier 930 carb fitted to a Vincent Comet. Also I have had the failed (melted) piston examined by an expert aeronautical engineer who specialises in combustion chamber physics. It was his VERY STRONG opinion that it was NOT a lean mix that caused the failure, but rather detonation. He recommended using the highest octane fuel available and also reducing the ignition advance to NO MORE then 32 degrees BTDC. So here is the conservative tuning configuration</p><p></p><p>#3 Slide,</p><p>Norton Commando style spray tube</p><p>Main Jet 240, </p><p>Needle Jet 105, </p><p>needle in centre groove,</p><p>RJ19 pilot jet</p><p> idle mixture screw 1 1/4 turns out. </p><p> </p><p>Timing set to 32 degrees BTDC at full advance</p><p></p><p>Martyn</p></blockquote><p></p>
[QUOTE="Martyn Goodwin, post: 46086, member: 2433"] [b]Amal Mk1 930/301PREM/A Carb for a Comet[/b] I installed a "new" Amal unit on my Comet some 2,000 miles back and it has transformed my bike. Easily starting , smooth idle and loads of power (when compared to the knackered old original unit It is a “improved” Amal Mk1 930/301PREM/A concentric. After consulting with Big Sid, I had it configured as follows; #3 Slide (hard anodised), 106 Needle Jet, 210 Main Jet, RJ19 Pilot, a Norton Commando style spray tube (which has the entire rear section –that faces the inlet valve – cut away), viton tipped float needle, “stay-up” float and a K&N air filter. I installed the new carb using a flange to flange stainless steel manifold I obtained from Jim Mosher in the USA. I profiled the inlet port opening on the head to provide a smooth gas flow thru the manifold and into the inlet port. I also installed a Bakelite heat insulator from a Norton, between the manifold and the carb. Taking note of the Amal instructions I used Nyloc nuts when securing the carb to the manifold and tightened them to just 4 foot pounds. At first I could not be happier with the result. BUT [SIZE=5][B]WARNING [/B][/SIZE] [B]December 9, 2013 update:[/B]: After a long run of a 100 miles or so at high speed the motor was overheating to the extent the the pipes blued badly and I lost a fair bit of compression. Internal examination revealed an overheated and damaged piston, broken top ring etc - so it seems I was running way too lean. Additional trials are underway following a rebuild and I started out with a 250 main jet and the needle in the bottom grove ( rich setting). . [B][SIZE=3]Current RECOMMENDATION , DEC 9, 2013[/SIZE][/B] After extensive road trials conducted over a number of weeks the following is the current suggested configuration for a Amal Mk1 Premier 930 carb fitted to a Vincent Comet. Also I have had the failed (melted) piston examined by an expert aeronautical engineer who specialises in combustion chamber physics. It was his VERY STRONG opinion that it was NOT a lean mix that caused the failure, but rather detonation. He recommended using the highest octane fuel available and also reducing the ignition advance to NO MORE then 32 degrees BTDC. So here is the conservative tuning configuration #3 Slide, Norton Commando style spray tube Main Jet 240, Needle Jet 105, needle in centre groove, RJ19 pilot jet idle mixture screw 1 1/4 turns out. Timing set to 32 degrees BTDC at full advance Martyn [/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
New Amal Premier 900 series Carb for Comets
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