brass float needle question

[81xsproject]

Is visible wear on the old brass type float needles bad for sealing?

[prometheus578]

Yup. The wear ring is where the needle sets in the hole of the seat. The constant opening and closing of this valve is what causes the wear. Also exacerbated by extremely fine particles of grit in the fuel that the filters can't catch. (Close on a piece of grit... cause a scratch) Enough scratches cause a ring. Too much of a ring causes a leak.
Float needles don't like to be disturbed, either. If yours have a ring, but they weren't leaking... they'll be leaking now, or soon after. Tricky business... if you take it out to inspect it, and put it back in rotated a quarter turn or so, it's wear pattern won't match up and it could leak. Some do, some don't. I always replace. ( I carry spares, and have been known to pull the carbs at a rest area and swap them out)
Any bike shop should have them... about $5 a needle. Bench test the carbs for leaks before remounting them on the bike