Carburetor float valve seat seal

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1987 Venture Royalle 13 DT. I have had issues with my carbs overflowing. I have taken them off to clean them. One of the carbs has a sticking float valve. The seat that the valve sits in has burrs inside that won't allow the valve to move smoothly. I have tried a few things to shave the inside without luck. I don't know how it got that way. It had been working before I took it apart. It is difficult to get anything straight down in there. I have a rebuild kit that has a replacement valve and seat. If I can't smooth it out how hard would it be to replace it? Are the correct caps available? How hard is it to dislodge the valve seat. 

Thanks!