A7SS carb set up

[BSA500]

On the tech forum I started a thread about a misfire but it should really be on here.
Background I have a A7 which I converted to SS spec ie alloy head higher comp etc. I have never been happy with the carb set up I had to run many years with an old 15/16 choke which was ok as it had been sleeved. I got what I thought was a 1" carb turned out to be 1 1/16 runs ok but appears rich 1/8 throttle up jerking no spit back raised the needle to its highest to get a better pick up because if lowered or a smaller jet used runs rough. Not keen to buy loads of jets/slides as that gets expensive I need all your combined knowledge to at least narrow my options(a new carb is not one of them shame).
Here are the current settings etc and a useful link I found

Carb 376/9
Main jet 240
Needle jet 107
Needle C
Pilot 30
Needle clip lowest position

Mag fine recent overhaul no problems plugs NGK B6ES runs much better with just those

Link   http://archives.jampot.dk/Technical/Carburation/Amal_Monobloc__numbers_type_and_use.pdf

[muskrat]

G'day BSA500,
                    you don't say what slide you have, which is where your trouble starts. I would also drop the needle jet back to a .106 or .1065. The 1 1/16" 376/9 has the same jetting as the 1" 376/16 bar the pilot and I would imagine that a 30 should work. I think your slide is the problem, either worn and letting too much air past or too lean cutaway.
Cheers

[BSA500]

Hi,
I dropped the needle back to 1065 and it was horrible spitty non responsive etc. The carb slide is a 3.5 and may be a little 'loose' not dreadful. Problem is the syptoms suggest if I am reading the tuning guide right rich on 1/8 throttle up ie jerking/surging with no spit back. God I hate tuning so do  buy a no4 slide or a 3.5

[muskrat]

G'day again,
                surging or hunting is usually lean. Rich is fluffy der,der,der. If you have a choke fitted, get to the problem point and close the choke. If it gets better you need to richen, if worse you need to lean out. The needle & jet work from about 1/3 to 3/4 throttle, the slide is just off pilot and will affect up to about 1/2. When playing with different carbs it can take quite a while to get it right. Try jetting a pair of 30mm Kehin flat slides for an A10 !!!
Cheers

[BSA500]

Ok that sounds like a plan I do have choke fitted so its worth a go thanks

[BSA500]

Nice day bit of time so tried to sort this out. Guess what no problems today one slight hiccup but ok  ,could put it down to warm weather. The only thing I have done is to reseal the exhausts to the head so poss it was the leaky exhaust and adjusted the valve gaps they were not miles out. Found at full throttle backing off it ran a little better so poss a larger main jet I think for the A7SS is 270? cyurrently running 240. So I will have to keep plugging away I might fit a new 3.5 slide to take some sloppyness out and maybe weakness. Any other suggestions?
Andy

[muskrat]

G'day Andy,
                good to hear of some progress. Sometimes other issues affect the carb.
Just try one thing at a time. Main jet first, but don't test it at 30mph in 4th, try 50mph in 3rd. If it picks up a little when the throttle is backed off a tad a richer jet is needed.
Next is pilot, worked out by how far in or out you have to screw the adjuster. Ideal is with the screw 1 1/2 turns out from seated.
Then it's the slide. Hold throttle at 1/4 and use the choke to determine whether you need to go richer (less cutaway) or leaner. Same with the needle at about 1/2 to 3/4 throttle. Always test at full operating temp.
It's all time consuming but at least your out riding.
Cheers