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Y S Carburetors
Posted: Mon Feb 07, 2022 5:36 pm
by jtpasto
Posted: Mon Feb 07, 2022 6:31 pm
by RICKG
hard to tell from the pics but I think 1 is a 950 the other a 637.
Posted: Mon Feb 07, 2022 9:02 pm
by wesk
I brightened the photo of the pair. The smooth surface one is a YS950S and the rusty surface one is a YS637S. Easy way to tell them apart is the diameter of the throttle bore or the alignment of the two base mounting studs.

Image from Craigs List AD

637S vs 950S from my album. The orientation of the two mounting studs is clearly seen. Also air horn inlet diameter difference is apparent.

Also from my album and you can see the throttle body diameter difference.
Posted: Tue Feb 08, 2022 6:10 pm
by RICKG
Yep I based my observation on what I could see of the throttle bodies.