float bowl drain screw gasket

[Jhurt]

1978 GS750.....When I rebuilt my carbs I used the Robert Barr gasket kit, all was well for awhile but then they started leaking through the float bowl drain screw, the seepage is very dark in color like the fuel has started to dissolve the o-rings. I then bought OEM Suzuki o-rings for the drain screws from Partzilla, same result: after a few months they started leaking. We have 10% ethanol in our gasoline here in the land of political corruption (Illinios) and I suspect that is causing my problem. After a complete teardown and rebuild of the entire motorcycle, literally every nut and bolt....this is the only leak and it's annoying me. Does anyone have a source for these o-rings that will resist ethanol blends, are the correct size etc??

[Gorminrider]

Make one from gasket paper. They last quite awhile. If you like a thin washer between bolt and paper gasket might extend life or it might not-I don't bother.
(Myself, I haven't seen any effect of gasohol on my bikes but it's hard to know how much is really in the gas despite the declaration on pumps)

[Big T]

Make an O ring from gasket paper?

Jhurt, I assume you tried to tighten the drain screws when they started leaking?

[Jhurt]

Yes I checked tightness, no problem there. May try the homemade suggestion, I have few different kinds of gasket materiel in the shop

[Nessism]

What about a Viton O-ring?

[Jhurt]

Viton would likely work but my Viton kit doesn’t have any small enough…does anyone know the correct size? Afraid if I pull one to measure it would be incorrect since they’re somewhat deteriorated

[Nessism]

Viton would likely work but my Viton kit doesn’t have any small enough…does anyone know the correct size? Afraid if I pull one to measure it would be incorrect since they’re somewhat deteriorated

Robert Barr posted information here with all the sizes of his O-ring kits.