Advise on Leaking Amal 276

[Riderusty]

I've rebuilt the AMAL 276 (remote float chamber carb) on my '53 A7. When I reinstalled the carburetor on the bike I saw it was leaking from where the bottom piece threads onto the carb body. I initially suspected the height of the float on the float needle but on removing the float I saw that the spring clip fits into a recess on the needle and I assume that the height of the float is therefore not adjustable. I had cleaned out sludge at the bottom of the float bowl earlier but now I noticed dirt where the float needle seats in the bottom of the float chamber. I cleaned this with carb cleaner and a Q-tip. The surface of the float needle and the seat both look good but I am wondering if I should lap the seat.

I am not a carburetor expert by any means, and this is my first experience with this type carb-any comments or advise here would be greatly appreciated.

Thanks!
Tom B.

[Angus]

I had similar experience with one of those, although not on a BSA. It leaked, cleaned it three times and lapped the needle, still leaked. Noticed it did not leak when bike was running but I don’t like dripping petrol near a magneto. Bought a float kit with needle etc. from Amal/Bulens, it still leaked. Talked to some guys in the club and they tell me they are call old leakies because they all leak and if it stopped when the bike is running then forget it so I have (well I have not, it still worries me)

[Riderusty]

Thanks, Angus--that's certainly, uhh, encouraging.  I agree that dripping gas is never a good thing.

Tom .

 

[scotty]

Mine was brand new and leaked pretty bad when it was on the side stand but not as bad on the centre stand .

I never did figure it out 

[jachenbach]

If you want to lap it, a bit of cigarette ash works surprising well to clean up brass surfaces.

[Black Sheep]

I have an original 276 on my '51 Star Twin. It never leaks. Well, actually it did once... The problem was that the clip which holds the float needle had fatigued (I know how it feels being the same age) and was letting the float move independently of the needle. It was intermittent and caused a bit of head scratching before I finally figured it out. I would also recommend a very gentle lapping of the needle in the seat. Thought, that's what they did to me when I dinged myself on my Norton. Ouch.

[Clive54bsa]

My '54 G/F has the same carb,  and it leaked whilst on the main stand, I bent the clip which holds the float needle and it slightly lowered the float and stopped the leaking, it still leaks on the side stand, so I turn off the fuel if I'm parking the bike temporarily.

[Craig]

If you look on the side of the main body where the mixing chamber union nut goes (see attached image as example) there is a small hole that is not covered by the thread of the nut. This is an overflow hole and there by design.
when bike is on side stand it will always leak here. Don't try cover it up, it is by design. if you use side stand a lot then possible to turn off taps before you cut the engine and run the fuel in carb down.

When bike is on main stand it should not leak too much. Might drip a bit but then stop if you have shut off fuel tap and when level drops below the hole. If it pours out here when on main stand then your float level is not correct and needs sorting.

[Greybeard]

I have that carb type on my Plungie. I haven't been aware of leaking from the carb but I do turn the tap off when parked. I also usually run the engine to empty the fuel bowl.
I did have some petrol escaping from the old cork type taps and running down the outside of the pipe down to the carb union. Been ok since I changed to the modern style taps.