What O ring are you getting this BS about? The bowl seal?
I have a needle and seat I can give you with the bowl seal. Used but should work.
96 XR650L, 96 Guzzi Sport, 07 BMW K1200GT,
86 Husky 400 XCE, 00 Husky Te 610 e, 1999 Husky TC610 SM, 2000 Cagiva GC; Google: TX7