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Concentric for Monobloc Domi 99

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I am having issues with the monobloc carb on my 1959 99 whereby she will only run with some choke on and has no power going up hill. I have cleaned all of the jets, raised the needle and adjusted the air screw, all to no effect. I am going to next replace all of the gaskets as the only thing remaining is an air leak.

However, one thought i did have prompted by talking to someone at a bike meet, was to swap the monobloc for a concentric. He had done it on his A10 and it had a lot of difference.

Has anyone done this? Would it be better? Realise it loses some of the authenticity but if it improves things then i'm willing to give it a try.

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Have you checked if flange is warped? Not uncommon on old carbs where someone in the past has excessively tightened the nuts. An air leak at the flange can easily be checked by spraying start gas around the flange with engine running.

On replacing Monoblocs with Concentrics are different opinions (of course). As the Monoblocs performed quite well back then, I believe they'll do it today, if in good order. On the other hand, I would replace it with a Concentric just because they are cheaper.

Mike

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Having had a concentric on the Atlas I soon swapped it for a Mono !. Much longer lasting and with far easier access to float chamber and jets. Better ,but yes a bit more expence. 

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hello mono bloc carburetors have served well for well over 65 years   so replace like with like,  concentric carburettors tend to run weak   and can be the cause overheating   having the right setting and carburetion is vital   for good running  and get to know   your carbrettors  and how they work  yours  anna j  

 



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