Im with COOP - 89 is modern to me !!!
(but then I remember Jones on a CR250 silver tank too)
There are also dedicated forums on the WWW for these brands and years - amazing the knowledge that is out there and cross match/fit parts too.
Marks Motorcycle Swapmeet is an amazing source too - he has a web and now FaceBook set up.
I have found that going to a Fiche site and find the part I am searching for, then take that part number and just search for it - that 'other machines it fits' or goes to comes up - did this on a vintage rebuild for the clutch 'ball and rod' set up and was searching for just the ball on this old YZ - come to find out, the parts search came up with it being used in Yamaha outboard motors and other engines...
RMATV parts fiche loads quick for OEM parts and makes it easy for a 'jump off point' for searching.
Good luck !!
Having done countless Frame Up restorations on vintage MX bikes - as these target bikes get older, its wise (if you can) to snag up bikes/motors etc from the same or comparable years (parts sharing) and start building your own parts warehouse - I did that with my YZ465 - parts are becoming very hard to find.
good luck !!
Post photos when done and in progress
OnS