I have raced 250R for 10 years, know them like the back of my hand. Call me at the shop and I can go over some things to look for. 88-89, swingarms crack up front and are about impossible to repair. The upper steering stem mounts break, and the frame just in front of the frame. Check out the counter balancer holder. The 88-89 years have better gears, clutch system, peg location, front spindles, just to name a few things.
Scott
919-832-5525