The float chamber should be free to pivot when the bottom banjo bolt is loosened, and if you move it backwards and forwards you will see that this raises and lowers it due to the 38 degree downdraught angle of the mixing chamber. In theory, using this method is a bit of a bodge, but in use the float chamber is never perfectly vertical anyway, because the bike is leaning from side to side, and going up and down hills, so in practice it works OK, and is much easier than trying to lower or raise the float needle off the float. Or are you saying that you have a horizontal carburettor on a separate stub ?
Brian
