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ES2 replacement carburettor?

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Hello all, can anyone tell me if there might be a modification carb for a 1949 ES2 which might make mine perform a bit better? I have had the pre-mono bloc original completely refurbished by stewart engineering of Lee on Solent ( the slide has been sleeved, a new needle and the bore honed to accept the new slide 0 but it seems to been introducing too much air and only runs smoothly when the air lever is closed. when I open the air lever ( when warmed up) the performance drops. I have set the air intake screw to2 1/2 turns out as suggested in the owners manual. The crazy thing is, that when first fitted to the bike it performed really well going as fast as its ever gone ( a whopping 65 m.p.h! but the other day just seemed to die. I have checked all the obvious things but have now run out of things to check - which is why I was considering changing the carb ( which would be a shame as its original) Any suggestions would be greatly appreciated. Thanks Glenn

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It would seem that the fuel/air ratio is upset. If it runs better with the air slide down this would tell me that there is not enough fuel getting through to balance the amount of air when the slide is up.

Have you checked your main jet for blockage?

Mike

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There isn't much that can suddenly go wrong without being obvious

The symptoms suggest a blockage somewhere. Have you dropped the jet block out ?

If you haven't done it before, it's best to drop them in a pan of boiling water and then tap gently upside down on a piece of dowel. Don't whack too hard as they can distort. The small drillings can then be checked / bown through. It can't be done with the block in-situ.

Does the carb body code have an 'R' suffix ?

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Previously michael_sullivan wrote:

It would seem that the fuel/air ratio is upset. If it runs better with the air slide down this would tell me that there is not enough fuel getting through to balance the amount of air when the slide is up.

Have you checked your main jet for blockage?

Mike

Many thanks for your advise Mike. I assumed that as I had filters in the tank no debris in the petrol would get through to the carb. but thinking about it it wouldnt need to be that big to block the jet. I will be investigating tomorrow and let you know the up shot. cheers Glenn

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Previously richard_payne wrote:

There isn't much that can suddenly go wrong without being obvious

The symptoms suggest a blockage somewhere. Have you dropped the jet block out ?

If you haven't done it before, it's best to drop them in a pan of boiling water and then tap gently upside down on a piece of dowel. Don't whack too hard as they can distort. The small drillings can then be checked / bown through. It can't be done with the block in-situ.

Does the carb body code have an 'R' suffix ?

Thanks for your advice Richard. I will be having a look tomorrow and will let you know if the carb has an R suffix. Cheers Glenn

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Check the petrol tank vent in cap is not partially blocked, also any in line fuel filters are clear. If it needs the chock to run, it is running far too lean a mixture andyou will be overheating the exhaust valve and piston crown, leading to premature failure.

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Yes Paul, if you are using a stainless exhaust valve it will be the piston crown that takes the hit first.

Remember that E 5 fuel contains oxygen and therefore runs weaker anyway. BP Ultimate @ E0 the stuff to use in most places.

It doesn't take much to block a main jet!

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Previously richard_payne wrote:

There isn't much that can suddenly go wrong without being obvious

The symptoms suggest a blockage somewhere. Have you dropped the jet block out ?

If you haven't done it before, it's best to drop them in a pan of boiling water and then tap gently upside down on a piece of dowel. Don't whack too hard as they can distort. The small drillings can then be checked / bown through. It can't be done with the block in-situ.

Does the carb body code have an 'R' suffix ?

the number on the carb body is 276AUD/R?. The good news is that without taking it apart, it cleared itself last night whilst driving home. But I know what to check now should it happen again. I think an in line fuel filter might be called for! cheers for your assistance. Glenn

 



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