The entire clutch is missing? Bummer, they are expensive. How about the bell housing, is it still there? I can get you the pulley diameter for a 1985 Bandit 200+ with a Cummins but I have no idea if it the same size as yours. What ever you do find out what Bandit says regarding clutch adjustment and engagement and follow their advice to the letter. Constantly think about adjusting the clutch (and changing out the knives and adjusting the bed knife) until you have no excuse for not pulling the cover and adjusting the clutch. Always grease the disk bearings morning and at noon. A chipper uses a lot of grease! Also keep the belts tight and the engine aligned, and changes the hydraulic filter on schedule.
BTW does your 200 have a flip down in-feed chute? Some older models did not. If yours doesn't ask Bandit about a retro fit kit.