The 85 kick starters were known for slipping, there was something updated on them in 86. the kick starter stuff will fit any year cases, but the clutch cover was different in 88 and 89 to correlate with another kickstarter change. Any kickstarter would fit with the correct clutch cover, or possibly by modifying the spacer. I believe there was a 10mm difference in the length of the spacers.
As Rich said above, spiritaces (Jon) had some for sale recently, look in the for sale section.