When I received the bike it was empty of fuel, so I did a bit carb cleaning ,the float chamber (which was full of oxidisation and "silt") replaced main jet , needle jet gaskets and seals and blew out all orifices with the airline.

While I was on I also renewed the fuel pipes ,replaced the corks in the fuel taps and just to keep things good cleaned the fuel tank out and lined it with Frosts tank kit.

Tonight I filled the tank up and let the fuel flow , great no leaks or weeps apart from the mouth of the carb:face_with_rolling_eyes: , so I thought stuck float , took the float chamber top off ...... no the float was free and at the top .


Now this is totally a novice asking the question:grin: ............. the float "needle" seats brass against brass :+1: , do these faces over the period become burred worn etc ? , so would I be correct in contemplating re seating the 2 pieces like you would lapp in an exhaust/intake valve , using the same paste or will that be too harsh ? also there seems to be alot of side to side play where the needle comes through into the float chamber or is that normal ? would just be better buying new replacement parts or a new carb from Burlens £290 or a float chamber around £110.


Just found the attached diagram on the net , is this position critical? as I had to move it slightly to accommodate the filter

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Thanks

Dave

email (option): davemb42@yahoo.com

I've been out in the garage , tested the float chamber.Filled it with fuel and the float worked fine , re sealing itself after pushing it down 3/4 times in succession.

what else to try I'm not sure , already had a new main and needle jet , could it be the valve block? think thats what they call it :grin: ( the brass piece inside the tube).Set the needle at No3 170 main .

email (option): davemb42@yahoo.com

The sketch above is from the Amal assembly card and was simply to ensure that the pre-assembled mixing chamber / float assemblies were correctly aligned when sent to BSA for original fitment. As the carb is horizontal, the angle will not affect float level.

The brass on brass needle / seat can be prone to flooding although once they're sorted, they usually stay that way for a long time. Fuel obviously needs to be 100% clean. It takes very little dust to cause problems. Lapping can help if not too bad but only very lightly and with nothing coarser than 'Brasso'. A very light tap onto the seat can also help - but certainly don't hammer it into the seat.

A new float chamber may help. There was a suggestion a while ago that Martyn Bratby could replace or re-face the seats but I haven't tried him for that. Current Amal chambers have a nylon float and needle with extra groove to accomodate the different locating system.

Using them is the best way to ensure that this sort of thing doesn't happen.

email (option): davemb42@yahoo.com

It may be simply that your fuel level is too high. There is a bleed hole on the left side of the main carb body, just above the bottom union nut to take care of any over fueling. There are two or three different heights of union nuts and an M20 should have the shortest one. Usually the problem will go away once the engine is running. You can't alter the height of the float but you can alter the height of the bowl with an extra washer. Ron

email (option): ronpier@talk21.com

email (option): davemb42@yahoo.com