JUST A FEW THOUGHTS AFTER SEEING THAT PAUL IS LOOKING FOR A 36mm BING.
A conclusion based on experience.
Before turning your engine off, turn your fuel cocks off and run the carby out! Over the years I have seen Bing carbies with black floats, white floats and pink floats?
?(your bike will start easier next time with a fresh dose of fuel in the bowl rather than a dose that has vapoured off it's octance rating! whilst it was standing).
Roughly thirty years ago I was scratching my head as to why my mixture(plug colours kept changing, becoming richer!!! It eventually came down to the fact that the fuel level in the bowl was some how steadily increasing from where I had set it months earlier. In young days I rode nearly every day, only killing the engine when I got home from the scrub, (instead of running it out) as not to annoy the neigbours.
And then it dawned the reason, "BING"O,,,,, old floats and white ones in particular eventually absorb fuel if they are left soaking in it. Therefore becoming heavier and as a result the fuel level in the bowl inreases.
proof in experiment. Weigh Your well dried out floats that haven't seen fuel for a while(gunpowder scales are perfect), then put them in a sealed glass of fuel for a month, get it out, dry the surface of and re-weigh it. There is the proof.
For Bings Black floats seem to be less prone to this phenomenam. I think its possible there may have been no such thing as pink Bing floats. Only black ones and white ones that turned pink because they absorbed the old red super grade fuel! The pink being the red "DYE" that was used as a marker to identify the old super grade(leaded) fuel.
Incidently I have worked for a couple of oil companies. It was considered that the old leaded fuel was alot more stable in retaining it's octane rating(RON or researh octane number) for up to six weeks in fact. Where as the newer unleaded fuels are considered to start loosing their octane value in as little as two weeks.
cheers Mick.
