from 89 to present kx500 motor design hasnt changed.while over past 18 years motor might of stayed the same but they did change various engine components.from 1988 to 1992 the kx500 was sold with 4 different ignition systems[Stator,cdi,coil and flywheel]in 89 and 90 some some KX500 came with lighting coil capability and others didnt.stealthy sells different year kx500 flywheel weights because there is a big difference in kx500 flywheels depending on what stator your bike was sold with.if you have 89 kx500 w/2 ignition coils on stator the flywheel is 1in. smaller in diameter and weighs 11oz. less than a 91 kx500 flywheel.the 91 stator uses 1 ignition coil and a sm.exciter coil.since stator only uses 1 ignition coil and has bigger flywheel there is room to add lighting coil on stator plate.lighting coil can not be added 89 kx500 stator.even though 88 thru 2003 the kx500 has changed these ignition components they are still fully interchangable the 91 ignition system will bolt right onto a 89 kx500 thats because they both still use same motor.
