Amal monobloc/ concentric

Information relating to the Matchless G2 or AJS Model 14 250cc Lightweight
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Amal monobloc/ concentric

Postby davehutch » Sat Jul 26, 2008 8:54 am

Just bought a matchless G2 250cc. It has a amal concentric carb on it.I know it should have a monobloc carb. Its not running very well and i think it is down to the carb. I have cleaned the carb but it is hard to set it up with the air screw. My qestion is can i get it to run properly with a concentric carb. or do i need a monobloc ? If so will any 376 monobloc do ? and what about the numbers after 376/ 99 that is what it say s in the book, but i have seen one on ebay with 376/ 14
will be clad of any advice Thanks Dave
----Only a biker knows why a dog sticks his head out of a car window.

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Amal monobloc/ concentric

Postby paul knapp » Sat Jul 26, 2008 1:11 pm

Dave, you don't need a Monobloc to have your engine running sweetly, as long as the Concentrics bore, jets and throttle valve (slide) are compatible to your bike.
You can convert almost any 376 carburettor into what you need as long as the bore is ... 1 1/16" I.D.(376 models come in several bore diameters.)
The G2 Monobloc has 1 1/16" bore, 180 main jet, 25 idle jet and a slide with a 3 1/2 cutaway. I could find no referance to a 376/ 14 only a 376/214 which is of a beesa twin, but appears to have the internal parts for your model except for the main jet, which can easily be changed.
Don't rush into buying off ebay till you are sure.

Paul

Edited by - paul knapp on 26 Jul 2008 1:17:16 PM
___ďAs a hobby for the technically minded, motorcycling provides great scope.Ē

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Amal monobloc/ concentric

Postby davehutch » Sun Jul 27, 2008 8:54 am

Thanks Paul
----Only a biker knows why a dog sticks his head out of a car window.

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Amal monobloc/ concentric

Postby 56G80S » Sun Jul 27, 2008 10:00 pm

Sure Paul's got this right, I had the AJS badge 14CSR, 1966.

I've used the concentric on the G80S that was on when I got it 30 years ago.

But it did work a lot better after dismantling, thorough cleaning and re-assembly with new gasket, o-rings, fibre washers and float needle!

Johnny B


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Amal monobloc/ concentric

Postby 56G80S » Sun Jul 27, 2008 10:00 pm

I got an error message that reply not sent and then there were 2 the same and I can't seem to delete second one, so am trying deleting all of the text in the second one! This message to avoid a blank space.

Johnny B



Edited by - 56G80S on 27 Jul 2008 10:21:08 PM

Edited by - 56G80S on 27 Jul 2008 10:22:12 PM

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Amal monobloc/ concentric

Postby davehutch » Mon Jul 28, 2008 3:33 pm

I have set Timing and valves cleaned carb out. I can now start it when cold first kick every time! But it then runs uneaven and start to miss and back fire, when i try to alter carb on the air screw it cuts out and then after wait for it to go cold to start it again.Any idea ?

Was going to meet the lads at the next local meet which is next wednesday to ask them and introduce myself.
----Only a biker knows why a dog sticks his head out of a car window.

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Amal monobloc/ concentric

Postby paul knapp » Mon Jul 28, 2008 3:52 pm

How's the spark plug?
Is there a good, continous flow of fuel to the carburettor?
___ďAs a hobby for the technically minded, motorcycling provides great scope.Ē

J.B.Nicholson

Don't worry about the world coming to an end today. It's already tomorrow in Australia!


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Amal monobloc/ concentric

Postby davehutch » Mon Jul 28, 2008 4:31 pm

Spark plug seems fine. and yes flow seems fine.
----Only a biker knows why a dog sticks his head out of a car window.

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Amal monobloc/ concentric

Postby CJU » Tue Jul 29, 2008 12:42 pm


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Amal monobloc/ concentric

Postby lawrence » Tue Jul 29, 2008 10:22 pm

Typical of Conway. Once he's started talking you can't stop him

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