This is a simple piece of advice but can be helpful. Most new throttle cables you can get for your British motorcycle with have cable stops that are too large to fit in the adjuster that is found on the top of the Amal carburetor. There is a simple fix shown here that will keep you from having
loose cables flopping around where they meet the carbs. Also, being that there are often adjusters at the throttle assembly as well as having an inline adjuster, a 3rd one at the carb is quite unnecessary, and you can do without one..
Measure the end of your throttle cable, they are typically just under a quarter inch, so a 1/4" drill bit should work great.
Here is the carb top reinstalled with the throttle cable now nestled snug.