BS 38 QUESTION

Oljo here again.Best I can tell I have the BS38's on my 1980 750 Twin.I've had em apart several times and I've been reading the forums when I can,I haven't seen an O ring yet! Mine just have the one fuel air mix screw and I expected to find them there. Can anyone tell me anything on this?Thanks in advance for any help.OLJOCLARK

I think on those carbs there is an oring on the mixture screw, drain screw, the fuel tubes between the carbs, and the float bowl gasket is an o ring.