I added an additional filter on my '81 R65, no filter screen over the tubes in the tank .
It has the filter in the fuel tap, but I was always getting fine sediment and a few globs of water in the carb bowls when I removed them .
After adding the extra filter, no sediment or water in the carb bowls .
It also helped out on my '82 LS, I purchased fuel line at a local auto parts store, it turned out, that the ' fuel ' line was vacuum line that was mis- identified, started seeing black sediment in the filter, removed it and found it was coming apart from the inside .