E: Engine 1951 Comet Carburation

David Wardingley

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VOC Member
Hello all,
I have a pre monobloc fitted to my comet ( series C) which gives rather an erratic tickover when it’s very warm. I would prefer to fit something more modern in the carb dept and wonder what advice members could offer. Amal concentric, Mikuni, Delortto ? I do have good results with the concentric on a Venom but that’s a different animal.
Regards.
David
 

vibrac

Well Known and Active Forum User
VOC Member
Mikuni or a new original 276 but not a Concentric I have had a feast of those this last season. For instance who wants a new carb whose pilots need to be drilled out before they will tick over ? the originals may have been OK but the latest iterations ......
 

Mike 40M

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My Venom came with a Mikuni, works well. My Comet came with a Concentric with drilled pilot, also works well. One thing I've never managed to figure out is which of all Mikuni needles is best for my Honda racer. Both Mikuni VM and Amal Concentric seems to work well on a Comet. Choose the one that you can get best advice on jetting.
 

vibrac

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VOC Member
Allen's in UK seem to have the settings
on the mikuni sorted on Comets 2 X 32mm and 1 X 34mm and I only had to change one pilot jet on one and that was me being finicky. I have had some problems with the rubber connector I cured one by using some of Ben's BMW hose suppliers stuff it's bright blue ! But it works
 

b'knighted

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Mikuni is top feed and on my Comet would not work on reserve. It needed a head of petrol to push past the airlock above the carb.
I have used 930 concentrics on Comets and have run a pair of 928s on the Knight for decades.
 

vibrac

Well Known and Active Forum User
VOC Member
They do work very well of course. And on top of this, Mik's are ugly and totally out of place on an old British Bike.
The concentrics date from over ten years after the demise of Vincents. They match with the dying products of British industry, Commandos, Triples, etc. not Vincents. Indeed monoblocs only just scraped in, and 'ugly' is in the eye of the beholder. For a matching number bike that's striving to be accurate a new 276, for riding and performance I would go for a Mikuni.
 
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