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Brand New Amal Carb for 3HW


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I need some advise..I have just purchased a new ‘Amal 276’ correct carb for my 3HW from a well known source not a considerable investment.

I know that the old carbs leak a bit especially when tickled but this new one to my surprise drips constantly from the bottom of the carb body. I also do not appear to be getting any fuel on the spark plug and the bike will not start. Refurbished mag/ Dino and a excellent spark, all gaskets in place and connections firm and tightened ( it’s brand new they should )

I have other bikes that drip from the carbs when going through the starting process but have always put this down to their age wear and tear.

Is the leaking prior to starting, a built in factor for some reason or another…?

Any enlightenment on this would be appreciated.



Never having had a brand new carb before I 

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I fitted a brand new Amal 276 to a friends 3HW, purchased from Hitchcocks. I assumed it was set up ready to go, but there was all sorts of issues....even flames. When I stripped the carb, everything was assembled loose. The jets were in just a couple of threads. I reassembled everything properly and on the following working day, I spoke to Alan Hitchcock about it. Apparently they build the carb to your spec from boxes of new parts, and this guy had just thrown it together under the assumption that the customer would take it apart for checking. I don't think Alan was very pleased with him.  Ron

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  • 1 month later...

Re my post of 29/12/22-

I have been persevering with this ‘brand new carb’ for my 3HW. I have sent it back to ‘Burlens Fuel Systems’ twice and the leak at least when the fuel taps are just turned on is now cured. But now I have black smoke blowing from the exhaust when giving the bike any throttle. It looks like I will be having to check the carb has the correct jets, needle setting etc. Not something that I would of expected from a new carb supplied specifically for a WD3HW. Ron P was right when he said he had to check the internals of a new carb he fitted, but my opinion is that when you lay out £460 for a carb it should be at least assembled correctly and with the correct jets, needle setting etc. I will post progress on this ‘NEW’ carb as the saga continues.

The maintenance book states NIL clearance on the valves, we have set them at 2 thou (don’t like nil clearances)

Opion especially from Ron P please..?

Rings and bore are okay.

Any other ideas of the cause of black smoke..?

Chris M


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I'm not sure you can atribute black smoke as a wrong jet, There is only one main jet which is hard for them to get wrong. (it's a 150 and easy to check). It's possible that you may have other issues. Have you run the bike on the road to clear any backlog of oil and get things properly up to temperature? Has the piston to skirt clearance been messured accurately? Has the bore been rebored or honed or deglazed? Valve stems to guides clearance within tollerance?  Lots of soot in the silencer?  Ron

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