The "sock" is probably slang that I learned from my Dad. But I've always seen a filter on the end of any fuel tube in a gas tank, car or motorcycle. It's usually long with mesh holes in it and looks like a sock.
. It's the first line of filtration. On a motorcycle it's usually on the pet cock feed tube that goes into the tank. It keeps large trash from getting in your petcock and further down the fuel system. These "socks" are usually pretty specific to the motorcycle so that would be an item that would probably require OEM matching.
If the filter you're talking about is external, it's probably less important to get an OEM match for that one. An aftermarket filter designed for gravity fed fuel that will fit in the hose will probably work.
Something to consider. If you're replacing your external fuel filter you may want to pull the petcock on the tank and look at the "sock" in the tank. It may also need replacing, or cleaning at least.
Since your external filter had rust in it then you may not have a "sock" at all. It's also possible that the first generation bikes didn't come with a screen on the petcock? But my guess is that someone just removed it over the years of ownership.
« Last Edit: October 05, 2016, 06:57:35 PM by MagnaMan »
'99 Magna (Halloween theme paint job)
Racetech Cartridge Emulators in front forks, Progressive 444s on the rear. Best mods I've ever made to this bike.