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
big TT carbs
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="Magnetoman" data-source="post: 54673" data-attributes="member: 2806"><p>I'm just back from the Middle East or I would have posted something about this sooner. I have a vintage 1-3/16" Amal 10TT9 mounted to a BSA C11 head in my office (doesn't everyone?...). I'm fairly certain this is the largest casting Amal made for this carburetor (other than the special one mentioned earlier in this thread, that I had not been aware of before now). Since I'm too tired to do anything productive, I just disassembled it to make some measurements.</p><p> </p><p>The bore for the slide is 1.498" dia. so that represents an upper limit on how much it could be bored out. However, the OD of the casting around the bore for the air itself is only ~1-1/2" so we couldn't get to the 1-1/2" without breaking through that wall. My TT is flange-mounted and there are two flats machined in the OD to allow clearance for the bolt heads. Since the spacing between those flats is 1.375" a brave person could increase the bore to, say, 1.374" without breaking through the casting. That certainly would push the upper limit to the limit. However, 1-5/16" seems somewhat reasonable, in that it would leave 0.031" wall under those two flats and plenty of material everywhere else (i.e. 0.094" walls) to provide the necessary mechanical support to keep vibrations from snapping the carburetor in two. </p><p> </p><p>A conservative racer (if that's not an oxymoron) might find 1-1/4" a safe place to stop with the boring bar on my carburetor. However, filling in those flats with epoxy (which only would be needed to stop possible air leaks, not to provide support) and using Allen-head bolts makes the 1-5/16" perfectly reasonable. Once could even contemplate a bit less than 1-3/8".</p></blockquote><p></p>
[QUOTE="Magnetoman, post: 54673, member: 2806"] I'm just back from the Middle East or I would have posted something about this sooner. I have a vintage 1-3/16" Amal 10TT9 mounted to a BSA C11 head in my office (doesn't everyone?...). I'm fairly certain this is the largest casting Amal made for this carburetor (other than the special one mentioned earlier in this thread, that I had not been aware of before now). Since I'm too tired to do anything productive, I just disassembled it to make some measurements. The bore for the slide is 1.498" dia. so that represents an upper limit on how much it could be bored out. However, the OD of the casting around the bore for the air itself is only ~1-1/2" so we couldn't get to the 1-1/2" without breaking through that wall. My TT is flange-mounted and there are two flats machined in the OD to allow clearance for the bolt heads. Since the spacing between those flats is 1.375" a brave person could increase the bore to, say, 1.374" without breaking through the casting. That certainly would push the upper limit to the limit. However, 1-5/16" seems somewhat reasonable, in that it would leave 0.031" wall under those two flats and plenty of material everywhere else (i.e. 0.094" walls) to provide the necessary mechanical support to keep vibrations from snapping the carburetor in two. A conservative racer (if that's not an oxymoron) might find 1-1/4" a safe place to stop with the boring bar on my carburetor. However, filling in those flats with epoxy (which only would be needed to stop possible air leaks, not to provide support) and using Allen-head bolts makes the 1-5/16" perfectly reasonable. Once could even contemplate a bit less than 1-3/8". [/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
big TT carbs
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