Hello,
You can get a UNI airfilter for the bike from AMS Racing (480) 966-0101 (Honda filter is discontinued), part number NU-4044ST. I "think" Motion-Pro might make a clutch cable (not sure on that...), if not I "might" have an extra to part with. As for an upper chain roller, the '79 CR125RZ didn't have one (only a lower and rear), however the '80 CR125RA did. The '79 roller's are also discontinued (they share the same roller's as the '78/'79 CR250R's), though I belive that Red Racer and Vintage Elsinore's have made repro's. Hope this helps...
Robert D. Hawes Jr.
Mesa, AZ.
mailto:rdElsinore@hotmail.com
(480) 807-1401