Y S Carburetors

jtpasto · Post by **jtpasto** » Mon Feb 07, 2022 5:36 pm

https://fortcollins.craigslist.org/pts/ ... 27968.html

Craigslist ad, not mine

RICKG · Post by **RICKG** » Mon Feb 07, 2022 6:31 pm

hard to tell from the pics but I think 1 is a 950 the other a 637.

Post by **wesk** » Mon Feb 07, 2022 9:02 pm

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.

RICKG · Post by **RICKG** » Tue Feb 08, 2022 6:10 pm

Yep I based my observation on what I could see of the throttle bodies.