BSA Owners' Club Workshop Discussions

The BSA Workshop => Singles => Topic started by: Mark Barkntrunk on 19 Aug, 2018, 17:27

Title: Air mixture screw on amal 276
Post by: Mark Barkntrunk on 19 Aug, 2018, 17:27
Can someone help please. My M20 with amal 276 carb is running very rich. Plugs turn black with soot after 2miles. I have adjusted the air mixture screw outward to it's limit before it falls out. But it's still sooty and not right. None of the plugs have been wet during adjustment. What else can I do?
Thanks
Mark
Title: Re: Air mixture screw on amal 276
Post by: ducati2242 on 19 Aug, 2018, 19:18
Think to make it leaner you screw it in . Start at 1.5 turns out . Could be a few things though have a read of these amal set up pages .
Title: Re: Air mixture screw on amal 276
Post by: ducati2242 on 19 Aug, 2018, 19:25
amal set up
Title: Re: Air mixture screw on amal 276
Post by: ducati2242 on 19 Aug, 2018, 19:25
amal set up 2
Title: Re: Air mixture screw on amal 276
Post by: ducati2242 on 19 Aug, 2018, 19:26
Amal set up 3
Title: Re: Air mixture screw on amal 276
Post by: Dean Southall on 20 Aug, 2018, 08:30
In addition to checking the right jets are fitted and the needle is in the correct slot have a check for flooding. This is pretty common with these bikes/carbs. New floats and float needles are readily available from Burlen, but give the float chamber a  good clean out and see if that helps first.
Title: Re: Air mixture screw on amal 276
Post by: Mike Farmer on 20 Aug, 2018, 10:25
 :)

Its also worth checking that you have the correct slide fitted

Mike 8) 8) 8)
Title: Re: Air mixture screw on amal 276
Post by: JulianS on 20 Aug, 2018, 11:38
Worn needle and needle jet cause rich running.
Title: Re: Air mixture screw on amal 276
Post by: STAR TWIN on 22 Aug, 2018, 06:27
Check carefully the clip holding the float needle in the float chamber. As these age, they can let go of the needle and your carb will suffer varying fuel problems, running rich being a common one.