I don't think anything else in the Yamaha lineup has ever shared the CV version of the carb, so it's possible that Yamaha lists only one jet. On the early slide version of the carb there are still a few options because that version was shared with the XT600 and a couple of other bikes, but they'd be entirely too big for your CV because they start at about #40. IIRC correctly the jumps are #40, #42, #45 and so on, but nothing smaller.
Spudrider may have some ideas for ya. They used a slightly more interesting and tweekable version on the Zongshens and he kinda be da' man on those.