You'll be suffering from Amalitis if you read this:

• Float level will effect the carburetion across the range of the instrument! Set the float level before you make any other adjustments.
• Main jets are the same for the Monobloc, Concentric, MK1 1/2 and MKII carburetors.
• As main jets age they tend to flow less fuel. Oxidation forms on the entrance to the jet orifice restricting fuel flow.
• Slides are unique for each Amal instrument and can vary by the size of the carburetor.
• Needle jets are unique for each Amal instrument and can vary by two stroke and four stroke models.
• Although needle jets never come in rebuild kits, they suffer the most wear in service.
• With use the metering orifice gets larger from the action of the needle being drawn through it.
• Spray tubes will vary with two and four stroke models and Concentrics set-up for Norton & Trident models.
• Two stroke spray tubes are cut at a slant front to back.
• Trident spray tubes are cut at a slant front to back.
• Norton 850 spray tubes are cut with a step.
• Needles are unique for each Amal instrument and vary by application.
• Concentric needles have a single letter above needle clip grooves, Concentric have concentric rings above needle clip grooves & MKII have alpha characters stamped above needle clip grooves.
• Float bowls, with the pressed in needle seat, are unique for each Amal instrument and can vary upon applications (gravity feed, fuel pump, competition, alcohol, or exotic fuels).
• Two stroke Concentrics can be identified by the sloping spray tube and removable pilot jet (124/026). Four stroke Concentrics have a pressed in pilot jet bush (622/107) in the air way passage.
• Four stroke Needle jets are crossed drilled to reduce the signal on the jet. The standard hole is .035" in diameter. Increasing the size leans out the mixture at low throttle openings. This effect is most pronounced while the fat portion of the needle is still in the needle jet. Be careful enlarging this hole. As little as .004" makes a big difference. Change the size .002" at a time and be sure to mark the jet to save embarrassment later.

If you are working on a bike that is running lean or rich at lower or mid-range throttle openings do not assume, even if you see Amal stamped on the needle jet. There have been both Amal and aftermarket needle jets that were not sized properly. I have seen after market jets marked .106 and measuring .109. Also, you will often find drilling flash at the bottom of the cross drilled holes. This will cause the jet to draw more fuel causing the bike to run rich. This can account for one carb to run richer than the other on Bonneville's.