The original 823 set-up was all Yoshimuira, everything. Head, crank, cam, pistons, springs, retainers, etc.
The 890 has an old Vance & Hines head, MTC pistons, Carillo rods, special grind Mega-cycle cam spec'd by Rick Stetson of Harry's Machined Parts. Also has a set of needle bearing rockers that as far as I know are one of two sets and I have them both! The carbs are factory Honda CR race carbs. These are not the newer ones with "CR" on them. They have no idle circuits built in, were used on factory Honda CR750's.
Maybe some of you older guys will recognize the Yosi hand-bent header that I am still kicking myself for selling years ago. Since I still own this I can look up any specs that you want. I also have a 1000 cc motor with Arias pistons. Thanks for the questions. Steve