I finally got my carbs adjusted pretty close to correct and my new muff ears fell apart internally. I changed to a new style muffler that I liked better and surprise surprise my carbs are no longer jetted right. I ended up with my Amal MK2 carbs with the left carb needle in the bottom groove and still too lean. I talked to an "old guy" and he told me to shim under the needle to enrich it a little. I have not heard about shiming like that but it appears to work. I added a .025" washer under the c-clip to raise the needle a bit and the plug chop looked a little better. Anybody know the pluses or minuses of that?