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Which Needle -Running Too Rich


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#1 Adam Johnson

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Posted 04 February 2019 - 06:12 PM

Hi all,

I have finished putting everything back together but I am running far to rich (the engine will die once it has gotten warm and the plugs are black with soot). I have an old hs4 carb from eBay that came with the AAU needle which I think is recommended in a stage 1 kit but I cannot lean it out enough so I need a rethink or else I cannot drive to a rolling road session.

I also have GY needle in my box of bits; is that going to be any better as a starting point before I get to a rolling road? If not, what should I order as a solid start?

Spec:

1275. Minispares inlet, maniflow lcb with full twin box maniflow system. K&n cone air filter, single HS4 carb. (In yellow as I am sure that will make all the difference).

#2 richmondclassicsnorthwales

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Posted 04 February 2019 - 06:26 PM

A HS4 carburetter more than likely with an AAU needle has come from a 1798cc MGB and is possibly one of 2 carburetters either the left or right hand side.

 

These 3 letter needles are Biased needles which have a little spring at the end of the needle which fits in to the damper part. They are also denoted to which way the needle sit when fitted

 

You GY needles are no good for this carburetter. These are fixed needles. If you use a ABB this is more suited to a 1275

 

You may need to change the jet, depends on any wear, but there are also another choice of needles you can use



#3 Adam Johnson

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Posted 04 February 2019 - 06:33 PM

Ok thanks; the gy needle was what came in the car when I bought it. Yes it’s a fixed needle. But in any case, you suggest ignore both and get an ABB (mini sport suggested an AAT).

Edited by Adam Johnson, 04 February 2019 - 06:33 PM.


#4 richmondclassicsnorthwales

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Posted 04 February 2019 - 06:45 PM

AAT needles were fitted to 1275 Midgets, but the best way to find a needle is rolling roads where they can discover which needle is best. The price though is eye watering !

 

Give that a AAT a go, the one you have fitted now is far too rich and will not work






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