he has a 1980 cb650 I think. One of the 650s.
+1 on everything you said, Johnie.
To take the float/needle out, just use a little punch or a brad or something slim and pointy and just gently press out that pivot pin. Sand it with a little very fine steel wool (clean it up real well after) or 1500 sand paper. Make sure that bugger's smooth. then clean up your float needle, make sure it's not 'sticky' and doesn't have any kind of residue on it.
I'm not sure if the plastic floats can spring leaks, but maybe they can. in that case, you may need a replacement.