Not that I am aware with, I would rather use the 4.4 Fd from the A1 though, don't take my word for it though, let someone that knows for sure tell you. I don't really see a problem using the A1 ring gear alone, however, using the ring gear alone will change the over tooth count.

For example, if the YS1 ring gear had a tooth count of 20 and a pinion count of 10 the gear ratio would be 2:1. If you throw the A1 ring gear in there, with the tooth count being 10, the gear ratio would be 10:10, effectively 1:1.