Worn AMAL carbs?

Information relating to the Matchless G12 or AJS Model 31 650cc twin
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Herman Geubels.
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Joined: Sat Jan 01, 2000 12:00 am
Location: BELGIUM

Worn AMAL carbs?

Post by Herman Geubels. »

I suspect wear on the AMAL 389/49 carbs of my '61 G12CSR. No problems at stationary and full throthle, but there is substantial power loss and sputtering in the mid-range. Can anyone tell me what the cause might be ? And if it's indeed wear on the jet-block and/or mixing body, can anyone recommend me a solution or a supplier that reconditions AMAL carbs? Thanks in advance!
Adrian Pancaldi
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Joined: Wed Jan 01, 1997 12:00 am
Location: New South Wales AUSTRALIA
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Worn AMAL carbs?

Post by Adrian Pancaldi »

If indeed you are sure that the spluttering is a fuel problem it could be worth investing in a set of new needle jets and needles.I experienced the same problem on my twin carb CSR ,and this cured the problem.These are easy items to replace and relatively inexpensive compared to having the carbs re-sleeved.The simplist way to see if the slides are worn is to lift them one at a time and try and rock it to and fro anything more than a few thou is excessive.Be sure when checking by this method that you are not lifting the slide rather than rocking it ,as this will give a false reading (the easiest way is with the carb off the manifold).If you find excessive movement, the carb can be re-sleeved by either re-sleeving the body or both the body and slide.Your local classic club should put you in the right direction of an engineer to perform the task.If not, try your local British bike spares store for a suitable person to do the job .Here in Australia there is a couple of people that i know of who recondition Amal carbs at around AUD$60.00 for re-sleeving each carb plus the cost of any gaskets needles jets etc.If you need anymore details my email is arby@start.com.au.I believe though that if worn slides were the problem you would have more of a flat spot than a splutter.Without actually expiriencing the problem first hand its hard to give a definite diagnosis.These things are generally a process of elimination,bestof luck I am interested in knowing what you come up with.
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silverarrow
Posts: 549
Joined: Mon Jan 01, 1990 12:00 am
Location: LEICESTERSHIRE UK

Worn AMAL carbs?

Post by silverarrow »

Dear Herman,

I can recommend someone in the UK who is able to offer comprehensive help and parts for the Amal carb. He can also help with pistons, rings & springs.

Martyn Braatby
The Coachworks
Lime Pit Lane
Huntington
Cannock
Staffs
England
WS12 4PA

Tel +44 1543 572583
Fax +44 1543 876202

I go along with the theory that changing the main jets and needles is a good place to start looking for your trouble.

Les Smith energy.man@fsbdial.co.uk
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