Carb insulator question

Just yesterday I installed my old manifolds as I just bought a set of Amal Premiers. I’ve been running a single Mikuni for the last 20 years. Manifolds had the thick insulators on head side and thin on carb side, which seemed to be the same material as insulators For as long as I’ve owned the bike, I have not fiddled with these, so not sure if they are original or not. So I left them on. As I think of it, these seem redundant since carbs came with o-ring.
 
Semitone said:
Just yesterday I installed my old manifolds as I just bought a set of Amal Premiers. I’ve been running a single Mikuni for the last 20 years. Manifolds had the thick insulators on head side and thin on carb side, which seemed to be the same material as insulators For as long as I’ve owned the bike, I have not fiddled with these, so not sure if they are original or not. So I left them on. As I think of it, these seem redundant since carbs came with o-ring.
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There should only be the o-ring on the carb side.
 
Semitone said:
Lineslinger, where did you get that fancy cable guide system for your Amals!?
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Do a search for Don Pender-Carb-synchronizing-gantry-platform etc. as there is a lot of information on this accessory of which I am a big fan.
It allows one to create a finite synchronized response from your throttle. Eliminates a lot of the manipulation needed with the original cable splitters.
Carb insulator question
Carb insulator question
Carb insulator question
 
Lineslinger said:
Do a search for Don Pender-Carb-synchronizing-gantry-platform etc. as there is a lot of information on this accessory of which I am a big fan.
It allows one to create a finite synchronized response from your throttle. Eliminates a lot of the manipulation needed with the original cable splitters.
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Wow. Very slick. As I was hooking up the cabling for the carbs yesterday, I was thinking the factory setup seems a bit crude for something so important for achieving a smooth running engine.
 
MichaelB said:
Looks like Amal has gone to 3/16" thick..
amalcarb.co.uk

Phenolic Spacer 30mm | Spacers | AMAL Carburetters

Phenolic Spacer 30mm
amalcarb.co.uk amalcarb.co.uk
That'll make the Ham Can more fun....
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Actually, AFAIK they have always had 5mm thick (about 3/16") and used to have 1/4" as well. Today on their web site and in their dealer catalog they only list 5mm thick and I checked those I have in stock and the are 5mm. Triumph and others have, AFAIK, always used the Amal parts when hard mounted. My old Triumph 500 has 1/4" from the factory.

To use those from Amal you have to file one edge as they will hit when side-to-side on a Norton.
 
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jseng1 said:
Much better to have a rubber hose as an insulator between the carb and manifold.
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Or stay stock except use the 69 and later Triumph manifold to carb system.

To mount two carbs (AN numbers):

2 - 70.0711 Thick O-ring 1/8" rather than 1/16"
2 - 70.9555 Cupped Washers
2 - 70.9554 Rubber Washers

The O-ring goes between the carb and manifold, then the rubber washer goes on, then the cup, and then the nut (I recommend a jam NyLock)

No metal to metal contact if centers on the studs and minimal if not.

It's a little fiddley to get the nuts tighten enough that the carbs don't move but the O-rings and rubber washers still ensuring no metal-to-metal.
 
Replying for SteveBorland:

I used the JS Motorsports, Billet Curved Inlet Manifolds, and the RGM Rubber Carb Manifold Flange Stubs Part No: 2932STRM. No modifications necessary. You can now remove the Insulator if desired. OR.....You could use the JS straight inlet manifold and the curved RGM flange stub.
 

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Yakatak said:
Replying for SteveBorland:

I used the JS Motorsports, Billet Curved Inlet Manifolds, and the RGM Rubber Carb Manifold Flange Stubs Part No: 2932STRM. No modifications necessary. You can now remove the Insulator if desired. OR.....You could use the JS straight inlet manifold and the curved RGM flange stub.
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Do those mani's still have a balance pipe connection?
I guess one added plus to not using the insulators....places carbs that much closed to head, giving a few vital more millimeters clearance from the HamCan if so equipped.
 
Tornado said:
Do those mani's still have a balance pipe connection?
I guess one added plus to not using the insulators....places carbs that much closed to head, giving a few vital more millimeters clearance from the HamCan if so equipped.
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The JS manifolds have balance ports close to the head end. They are smaller diameter than the stock ones. I will assume that Jim knows best. The JS manifolds are the same length as the stock ones, but the carb end slips into the rubber stub so the combo is shorter than stock.
 
Yakatak said:
The JS manifolds have balance ports close to the head end. They are smaller diameter than the stock ones. I will assume that Jim knows best. The JS manifolds are the same length as the stock ones, but the carb end slips into the rubber stub so the combo is shorter than stock.
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What carbs are they made for?
 
marshg246 said:
What carbs are they made for?
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No flange on the carb end, so ...no particular carb. The JC manifolds ID tapers from 33mm at the carb end to 32mm at the flange exit (head). RGM's rubber stubs appear to be available in 30, 32, and 34mm ID. I used the 32mm with a Fullauto head.
 
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