Pegs to suit pitbikes work.
Pegs to suit Honda XRs work.
Pegs to suit later YZs work with a bit of tweaking.
Pretty sure that pegs to suit PW50s work(!).
Pretty sure that pegs to suit The steel framed Honda CRs work.
I get a bit annoyed by the Ebay listings and parts books that say things like "Yamaha YZ125, 250, 490, 1985 and newer", because anything that fits an 85 model will fit every other Yamaha since they dropped the whacky pegs mounts that thy used on the early MXers (YZ & MX, before 1977).