The newer the better IMO.
The ignition changed to digital electronic in 1990, along with some modest changes to the wiring harness, pickup coils and the flywheel. Also the starter went from a 2-pole motor to a 4-pole motor in 1990.
In 1993 larger Forks and better brakes were added
In 1996 the block was changed and had a Spin-on Oil Filter and a Better R/R was used.
And 1999 and newer had a few more upgrades (like updated Oil Assembly, Shifter Fork, etc.).
But no matter what year you look at be sure to test drive it and run it up to 8K rpm or so in 1st, 2nd and 3rd gear to make sure it doesn't jump out of gear at all. (ONLY After the Bike is warmed up !!!!!)
